feat: add oauth2 code verifier

* fix: ensure oauth state param matches before finishing oauth flow Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> * chore: upgrade openid-client to v6 Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> * feat: use PKCE for oauth2 on supported clients Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> * feat: use state and PKCE in mobile app Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> * fix: remove obsolete oauth repository init Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> * fix: rewrite callback url if mobile redirect url is enabled Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> * fix: propagate oidc client error cause when oauth callback fails Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> * fix: adapt auth service tests to required state and PKCE params Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> * fix: update sdk types Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> * fix: adapt oauth e2e test to work with PKCE Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> * fix: allow insecure (http) oauth clients Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> --------- Signed-off-by: Tin Pecirep <tin.pecirep@gmail.com> Co-authored-by: Jason Rasmussen <jason@rasm.me>
2025-04-23 16:05:00 +07:00 · 2025-04-23 16:05:00 +07:00 · b7a0cf2470
parent 13d6bd67b1
commit b7a0cf2470
18 changed files with 469 additions and 192 deletions
--- a/e2e/src/api/specs/oauth.e2e-spec.ts
+++ b/e2e/src/api/specs/oauth.e2e-spec.ts
@ -6,6 +6,7 @@ import {
  startOAuth,
  updateConfig,
 } from '@immich/sdk';
+import { createHash, randomBytes } from 'node:crypto';
 import { errorDto } from 'src/responses';
 import { OAuthClient, OAuthUser } from 'src/setup/auth-server';
 import { app, asBearerAuth, baseUrl, utils } from 'src/utils';
@ -21,18 +22,30 @@ const mobileOverrideRedirectUri = 'https://photos.immich.app/oauth/mobile-redire

 const redirect = async (url: string, cookies?: string[]) => {
  const { headers } = await request(url)
-    .get('/')
+    .get('')
    .set('Cookie', cookies || []);
  return { cookies: (headers['set-cookie'] as unknown as string[]) || [], location: headers.location };
 };

+// Function to generate a code challenge from the verifier
+const generateCodeChallenge = async (codeVerifier: string): Promise<string> => {
+  const hashed = createHash('sha256').update(codeVerifier).digest();
+  return hashed.toString('base64url');
+};
+
 const loginWithOAuth = async (sub: OAuthUser | string, redirectUri?: string) => {
-  const { url } = await startOAuth({ oAuthConfigDto: { redirectUri: redirectUri ?? `${baseUrl}/auth/login` } });
+  const state = randomBytes(16).toString('base64url');
+  const codeVerifier = randomBytes(64).toString('base64url');
+  const codeChallenge = await generateCodeChallenge(codeVerifier);
+
+  const { url } = await startOAuth({
+    oAuthConfigDto: { redirectUri: redirectUri ?? `${baseUrl}/auth/login`, state, codeChallenge },
+  });

  // login
  const response1 = await redirect(url.replace(authServer.internal, authServer.external));
  const response2 = await request(authServer.external + response1.location)
-    .post('/')
+    .post('')
    .set('Cookie', response1.cookies)
    .type('form')
    .send({ prompt: 'login', login: sub, password: 'password' });
@ -40,7 +53,7 @@ const loginWithOAuth = async (sub: OAuthUser | string, redirectUri?: string) =>
  // approve
  const response3 = await redirect(response2.header.location, response1.cookies);
  const response4 = await request(authServer.external + response3.location)
-    .post('/')
+    .post('')
    .type('form')
    .set('Cookie', response3.cookies)
    .send({ prompt: 'consent' });
@ -51,9 +64,9 @@ const loginWithOAuth = async (sub: OAuthUser | string, redirectUri?: string) =>
  expect(redirectUrl).toBeDefined();
  const params = new URL(redirectUrl).searchParams;
  expect(params.get('code')).toBeDefined();
-  expect(params.get('state')).toBeDefined();
+  expect(params.get('state')).toBe(state);

-  return redirectUrl;
+  return { url: redirectUrl, state, codeVerifier };
 };

 const setupOAuth = async (token: string, dto: Partial<SystemConfigOAuthDto>) => {
@ -119,9 +132,42 @@ describe(`/oauth`, () => {
      expect(body).toEqual(errorDto.badRequest(['url should not be empty']));
    });

-    it('should auto register the user by default', async () => {
-      const url = await loginWithOAuth('oauth-auto-register');
+    it(`should throw an error if the state is not provided`, async () => {
+      const { url } = await loginWithOAuth('oauth-auto-register');
      const { status, body } = await request(app).post('/oauth/callback').send({ url });
+      expect(status).toBe(400);
+      expect(body).toEqual(errorDto.badRequest('OAuth state is missing'));
+    });
+
+    it(`should throw an error if the state mismatches`, async () => {
+      const callbackParams = await loginWithOAuth('oauth-auto-register');
+      const { state } = await loginWithOAuth('oauth-auto-register');
+      const { status, body } = await request(app)
+        .post('/oauth/callback')
+        .send({ ...callbackParams, state });
+      expect(status).toBeGreaterThanOrEqual(400);
+    });
+
+    it(`should throw an error if the codeVerifier is not provided`, async () => {
+      const { url, state } = await loginWithOAuth('oauth-auto-register');
+      const { status, body } = await request(app).post('/oauth/callback').send({ url, state });
+      expect(status).toBe(400);
+      expect(body).toEqual(errorDto.badRequest('OAuth code verifier is missing'));
+    });
+
+    it(`should throw an error if the codeVerifier doesn't match the challenge`, async () => {
+      const callbackParams = await loginWithOAuth('oauth-auto-register');
+      const { codeVerifier } = await loginWithOAuth('oauth-auto-register');
+      const { status, body } = await request(app)
+        .post('/oauth/callback')
+        .send({ ...callbackParams, codeVerifier });
+      console.log(body);
+      expect(status).toBeGreaterThanOrEqual(400);
+    });
+
+    it('should auto register the user by default', async () => {
+      const callbackParams = await loginWithOAuth('oauth-auto-register');
+      const { status, body } = await request(app).post('/oauth/callback').send(callbackParams);
      expect(status).toBe(201);
      expect(body).toMatchObject({
        accessToken: expect.any(String),
@ -132,16 +178,30 @@ describe(`/oauth`, () => {
      });
    });

+    it('should allow passing state and codeVerifier via cookies', async () => {
+      const { url, state, codeVerifier } = await loginWithOAuth('oauth-auto-register');
+      const { status, body } = await request(app)
+        .post('/oauth/callback')
+        .set('Cookie', [`immich_oauth_state=${state}`, `immich_oauth_code_verifier=${codeVerifier}`])
+        .send({ url });
+      expect(status).toBe(201);
+      expect(body).toMatchObject({
+        accessToken: expect.any(String),
+        userId: expect.any(String),
+        userEmail: 'oauth-auto-register@immich.app',
+      });
+    });
+
    it('should handle a user without an email', async () => {
-      const url = await loginWithOAuth(OAuthUser.NO_EMAIL);
-      const { status, body } = await request(app).post('/oauth/callback').send({ url });
+      const callbackParams = await loginWithOAuth(OAuthUser.NO_EMAIL);
+      const { status, body } = await request(app).post('/oauth/callback').send(callbackParams);
      expect(status).toBe(400);
      expect(body).toEqual(errorDto.badRequest('OAuth profile does not have an email address'));
    });

    it('should set the quota from a claim', async () => {
-      const url = await loginWithOAuth(OAuthUser.WITH_QUOTA);
-      const { status, body } = await request(app).post('/oauth/callback').send({ url });
+      const callbackParams = await loginWithOAuth(OAuthUser.WITH_QUOTA);
+      const { status, body } = await request(app).post('/oauth/callback').send(callbackParams);
      expect(status).toBe(201);
      expect(body).toMatchObject({
        accessToken: expect.any(String),
@ -154,8 +214,8 @@ describe(`/oauth`, () => {
    });

    it('should set the storage label from a claim', async () => {
-      const url = await loginWithOAuth(OAuthUser.WITH_USERNAME);
-      const { status, body } = await request(app).post('/oauth/callback').send({ url });
+      const callbackParams = await loginWithOAuth(OAuthUser.WITH_USERNAME);
+      const { status, body } = await request(app).post('/oauth/callback').send(callbackParams);
      expect(status).toBe(201);
      expect(body).toMatchObject({
        accessToken: expect.any(String),
@ -176,8 +236,8 @@ describe(`/oauth`, () => {
        buttonText: 'Login with Immich',
        signingAlgorithm: 'RS256',
      });
-      const url = await loginWithOAuth('oauth-RS256-token');
-      const { status, body } = await request(app).post('/oauth/callback').send({ url });
+      const callbackParams = await loginWithOAuth('oauth-RS256-token');
+      const { status, body } = await request(app).post('/oauth/callback').send(callbackParams);
      expect(status).toBe(201);
      expect(body).toMatchObject({
        accessToken: expect.any(String),
@ -196,8 +256,8 @@ describe(`/oauth`, () => {
        buttonText: 'Login with Immich',
        profileSigningAlgorithm: 'RS256',
      });
-      const url = await loginWithOAuth('oauth-signed-profile');
-      const { status, body } = await request(app).post('/oauth/callback').send({ url });
+      const callbackParams = await loginWithOAuth('oauth-signed-profile');
+      const { status, body } = await request(app).post('/oauth/callback').send(callbackParams);
      expect(status).toBe(201);
      expect(body).toMatchObject({
        userId: expect.any(String),
@ -213,8 +273,8 @@ describe(`/oauth`, () => {
        buttonText: 'Login with Immich',
        signingAlgorithm: 'something-that-does-not-work',
      });
-      const url = await loginWithOAuth('oauth-signed-bad');
-      const { status, body } = await request(app).post('/oauth/callback').send({ url });
+      const callbackParams = await loginWithOAuth('oauth-signed-bad');
+      const { status, body } = await request(app).post('/oauth/callback').send(callbackParams);
      expect(status).toBe(500);
      expect(body).toMatchObject({
        error: 'Internal Server Error',
@ -235,8 +295,8 @@ describe(`/oauth`, () => {
      });

      it('should not auto register the user', async () => {
-        const url = await loginWithOAuth('oauth-no-auto-register');
-        const { status, body } = await request(app).post('/oauth/callback').send({ url });
+        const callbackParams = await loginWithOAuth('oauth-no-auto-register');
+        const { status, body } = await request(app).post('/oauth/callback').send(callbackParams);
        expect(status).toBe(400);
        expect(body).toEqual(errorDto.badRequest('User does not exist and auto registering is disabled.'));
      });
@ -247,8 +307,8 @@ describe(`/oauth`, () => {
          email: 'oauth-user3@immich.app',
          password: 'password',
        });
-        const url = await loginWithOAuth('oauth-user3');
-        const { status, body } = await request(app).post('/oauth/callback').send({ url });
+        const callbackParams = await loginWithOAuth('oauth-user3');
+        const { status, body } = await request(app).post('/oauth/callback').send(callbackParams);
        expect(status).toBe(201);
        expect(body).toMatchObject({
          userId,
@ -286,13 +346,15 @@ describe(`/oauth`, () => {
    });

    it('should auto register the user by default', async () => {
-      const url = await loginWithOAuth('oauth-mobile-override', 'app.immich:///oauth-callback');
-      expect(url).toEqual(expect.stringContaining(mobileOverrideRedirectUri));
+      const callbackParams = await loginWithOAuth('oauth-mobile-override', 'app.immich:///oauth-callback');
+      expect(callbackParams.url).toEqual(expect.stringContaining(mobileOverrideRedirectUri));

      // simulate redirecting back to mobile app
-      const redirectUri = url.replace(mobileOverrideRedirectUri, 'app.immich:///oauth-callback');
+      const url = callbackParams.url.replace(mobileOverrideRedirectUri, 'app.immich:///oauth-callback');

-      const { status, body } = await request(app).post('/oauth/callback').send({ url: redirectUri });
+      const { status, body } = await request(app)
+        .post('/oauth/callback')
+        .send({ ...callbackParams, url });
      expect(status).toBe(201);
      expect(body).toMatchObject({
        accessToken: expect.any(String),
--- a/mobile/lib/services/oauth.service.dart
+++ b/mobile/lib/services/oauth.service.dart
@ -13,6 +13,8 @@ class OAuthService {

  Future<String?> getOAuthServerUrl(
    String serverUrl,
+    String state,
+    String codeChallenge,
  ) async {
    // Resolve API server endpoint from user provided serverUrl
    await _apiService.resolveAndSetEndpoint(serverUrl);
@ -22,7 +24,11 @@ class OAuthService {
    );

    final dto = await _apiService.oAuthApi.startOAuth(
-      OAuthConfigDto(redirectUri: redirectUri),
+      OAuthConfigDto(
+        redirectUri: redirectUri,
+        state: state,
+        codeChallenge: codeChallenge,
+      ),
    );

    final authUrl = dto?.url;
@ -31,7 +37,11 @@ class OAuthService {
    return authUrl;
  }

-  Future<LoginResponseDto?> oAuthLogin(String oauthUrl) async {
+  Future<LoginResponseDto?> oAuthLogin(
+    String oauthUrl,
+    String state,
+    String codeVerifier,
+  ) async {
    String result = await FlutterWebAuth2.authenticate(
      url: oauthUrl,
      callbackUrlScheme: callbackUrlScheme,
@ -49,6 +59,8 @@ class OAuthService {
    return await _apiService.oAuthApi.finishOAuth(
      OAuthCallbackDto(
        url: result,
+        state: state,
+        codeVerifier: codeVerifier,
      ),
    );
  }
--- a/mobile/lib/widgets/forms/login/login_form.dart
+++ b/mobile/lib/widgets/forms/login/login_form.dart
@ -1,6 +1,9 @@
+import 'dart:convert';
 import 'dart:io';
+import 'dart:math';

 import 'package:auto_route/auto_route.dart';
+import 'package:crypto/crypto.dart';
 import 'package:easy_localization/easy_localization.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
@ -203,13 +206,32 @@ class LoginForm extends HookConsumerWidget {
      }
    }

+    String generateRandomString(int length) {
+      final random = Random.secure();
+      return base64Url
+          .encode(List<int>.generate(32, (i) => random.nextInt(256)));
+    }
+
+    Future<String> generatePKCECodeChallenge(String codeVerifier) async {
+      var bytes = utf8.encode(codeVerifier);
+      var digest = sha256.convert(bytes);
+      return base64Url.encode(digest.bytes).replaceAll('=', '');
+    }
+
    oAuthLogin() async {
      var oAuthService = ref.watch(oAuthServiceProvider);
      String? oAuthServerUrl;

+      final state = generateRandomString(32);
+      final codeVerifier = generateRandomString(64);
+      final codeChallenge = await generatePKCECodeChallenge(codeVerifier);
+
      try {
-        oAuthServerUrl = await oAuthService
-            .getOAuthServerUrl(sanitizeUrl(serverEndpointController.text));
+        oAuthServerUrl = await oAuthService.getOAuthServerUrl(
+          sanitizeUrl(serverEndpointController.text),
+          state,
+          codeChallenge,
+        );

        isLoading.value = true;

@ -230,8 +252,11 @@ class LoginForm extends HookConsumerWidget {

      if (oAuthServerUrl != null) {
        try {
-          final loginResponseDto =
-              await oAuthService.oAuthLogin(oAuthServerUrl);
+          final loginResponseDto = await oAuthService.oAuthLogin(
+            oAuthServerUrl,
+            state,
+            codeVerifier,
+          );

          if (loginResponseDto == null) {
            return;
--- a/mobile/openapi/lib/model/o_auth_callback_dto.dart
+++ b/mobile/openapi/lib/model/o_auth_callback_dto.dart
@ -14,25 +14,36 @@ class OAuthCallbackDto {
  /// Returns a new [OAuthCallbackDto] instance.
  OAuthCallbackDto({
    required this.url,
+    required this.state,
+    required this.codeVerifier,
  });

  String url;
+  String state;
+  String codeVerifier;

  @override
-  bool operator ==(Object other) => identical(this, other) || other is OAuthCallbackDto &&
-    other.url == url;
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is OAuthCallbackDto &&
+          other.url == url &&
+          other.state == state &&
+          other.codeVerifier == codeVerifier;

  @override
  int get hashCode =>
-    // ignore: unnecessary_parenthesis
-    (url.hashCode);
+      // ignore: unnecessary_parenthesis
+      (url.hashCode) + (state.hashCode) + (codeVerifier.hashCode);

  @override
-  String toString() => 'OAuthCallbackDto[url=$url]';
+  String toString() =>
+      'OAuthCallbackDto[url=$url, state=$state, codeVerifier=$codeVerifier]';

  Map<String, dynamic> toJson() {
    final json = <String, dynamic>{};
-      json[r'url'] = this.url;
+    json[r'url'] = this.url;
+    json[r'state'] = this.state;
+    json[r'codeVerifier'] = this.codeVerifier;
    return json;
  }

@ -46,12 +57,17 @@ class OAuthCallbackDto {

      return OAuthCallbackDto(
        url: mapValueOfType<String>(json, r'url')!,
+        state: mapValueOfType<String>(json, r'state')!,
+        codeVerifier: mapValueOfType<String>(json, r'codeVerifier')!,
      );
    }
    return null;
  }

-  static List<OAuthCallbackDto> listFromJson(dynamic json, {bool growable = false,}) {
+  static List<OAuthCallbackDto> listFromJson(
+    dynamic json, {
+    bool growable = false,
+  }) {
    final result = <OAuthCallbackDto>[];
    if (json is List && json.isNotEmpty) {
      for (final row in json) {
@ -79,13 +95,19 @@ class OAuthCallbackDto {
  }

  // maps a json object with a list of OAuthCallbackDto-objects as value to a dart map
-  static Map<String, List<OAuthCallbackDto>> mapListFromJson(dynamic json, {bool growable = false,}) {
+  static Map<String, List<OAuthCallbackDto>> mapListFromJson(
+    dynamic json, {
+    bool growable = false,
+  }) {
    final map = <String, List<OAuthCallbackDto>>{};
    if (json is Map && json.isNotEmpty) {
      // ignore: parameter_assignments
      json = json.cast<String, dynamic>();
      for (final entry in json.entries) {
-        map[entry.key] = OAuthCallbackDto.listFromJson(entry.value, growable: growable,);
+        map[entry.key] = OAuthCallbackDto.listFromJson(
+          entry.value,
+          growable: growable,
+        );
      }
    }
    return map;
@ -94,6 +116,7 @@ class OAuthCallbackDto {
  /// The list of required keys that must be present in a JSON.
  static const requiredKeys = <String>{
    'url',
+    'state',
+    'codeVerifier',
  };
 }
-
--- a/mobile/openapi/lib/model/o_auth_config_dto.dart
+++ b/mobile/openapi/lib/model/o_auth_config_dto.dart
@ -14,25 +14,36 @@ class OAuthConfigDto {
  /// Returns a new [OAuthConfigDto] instance.
  OAuthConfigDto({
    required this.redirectUri,
+    required this.state,
+    required this.codeChallenge,
  });

  String redirectUri;
+  String state;
+  String codeChallenge;

  @override
-  bool operator ==(Object other) => identical(this, other) || other is OAuthConfigDto &&
-    other.redirectUri == redirectUri;
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is OAuthConfigDto &&
+          other.redirectUri == redirectUri &&
+          other.state == state &&
+          other.codeChallenge == codeChallenge;

  @override
  int get hashCode =>
-    // ignore: unnecessary_parenthesis
-    (redirectUri.hashCode);
+      // ignore: unnecessary_parenthesis
+      (redirectUri.hashCode) + (state.hashCode) + (codeChallenge.hashCode);

  @override
-  String toString() => 'OAuthConfigDto[redirectUri=$redirectUri]';
+  String toString() =>
+      'OAuthConfigDto[redirectUri=$redirectUri, state=$state, codeChallenge=$codeChallenge]';

  Map<String, dynamic> toJson() {
    final json = <String, dynamic>{};
-      json[r'redirectUri'] = this.redirectUri;
+    json[r'redirectUri'] = this.redirectUri;
+    json[r'state'] = this.state;
+    json[r'codeChallenge'] = this.codeChallenge;
    return json;
  }

@ -46,12 +57,17 @@ class OAuthConfigDto {

      return OAuthConfigDto(
        redirectUri: mapValueOfType<String>(json, r'redirectUri')!,
+        state: mapValueOfType<String>(json, r'state')!,
+        codeChallenge: mapValueOfType<String>(json, r'codeChallenge')!,
      );
    }
    return null;
  }

-  static List<OAuthConfigDto> listFromJson(dynamic json, {bool growable = false,}) {
+  static List<OAuthConfigDto> listFromJson(
+    dynamic json, {
+    bool growable = false,
+  }) {
    final result = <OAuthConfigDto>[];
    if (json is List && json.isNotEmpty) {
      for (final row in json) {
@ -79,13 +95,19 @@ class OAuthConfigDto {
  }

  // maps a json object with a list of OAuthConfigDto-objects as value to a dart map
-  static Map<String, List<OAuthConfigDto>> mapListFromJson(dynamic json, {bool growable = false,}) {
+  static Map<String, List<OAuthConfigDto>> mapListFromJson(
+    dynamic json, {
+    bool growable = false,
+  }) {
    final map = <String, List<OAuthConfigDto>>{};
    if (json is Map && json.isNotEmpty) {
      // ignore: parameter_assignments
      json = json.cast<String, dynamic>();
      for (final entry in json.entries) {
-        map[entry.key] = OAuthConfigDto.listFromJson(entry.value, growable: growable,);
+        map[entry.key] = OAuthConfigDto.listFromJson(
+          entry.value,
+          growable: growable,
+        );
      }
    }
    return map;
@ -94,6 +116,7 @@ class OAuthConfigDto {
  /// The list of required keys that must be present in a JSON.
  static const requiredKeys = <String>{
    'redirectUri',
+    'state',
+    'codeChallenge',
  };
 }
-
--- a/mobile/pubspec.lock
+++ b/mobile/pubspec.lock
@ -303,7 +303,7 @@ packages:
    source: hosted
    version: "0.3.4+2"
  crypto:
-    dependency: transitive
+    dependency: "direct main"
    description:
      name: crypto
      sha256: "1e445881f28f22d6140f181e07737b22f1e099a5e1ff94b0af2f9e4a463f4855"
--- a/mobile/pubspec.yaml
+++ b/mobile/pubspec.yaml
@ -22,6 +22,7 @@ dependencies:
  collection: ^1.18.0
  connectivity_plus: ^6.1.3
  crop_image: ^1.0.16
+  crypto: ^3.0.6
  device_info_plus: ^11.3.3
  dynamic_color: ^1.7.0
  easy_image_viewer: ^1.5.1
--- a/open-api/immich-openapi-specs.json
+++ b/open-api/immich-openapi-specs.json
@ -10354,6 +10354,12 @@
      },
      "OAuthCallbackDto": {
        "properties": {
+          "codeVerifier": {
+            "type": "string"
+          },
+          "state": {
+            "type": "string"
+          },
          "url": {
            "type": "string"
          }
@ -10365,8 +10371,14 @@
      },
      "OAuthConfigDto": {
        "properties": {
+          "codeChallenge": {
+            "type": "string"
+          },
          "redirectUri": {
            "type": "string"
+          },
+          "state": {
+            "type": "string"
          }
        },
        "required": [
--- a/open-api/typescript-sdk/src/fetch-client.ts
+++ b/open-api/typescript-sdk/src/fetch-client.ts
@ -688,12 +688,16 @@ export type TestEmailResponseDto = {
 };
 export type OAuthConfigDto = {
    redirectUri: string;
+    state?: string;
+    codeChallenge?: string;
 };
 export type OAuthAuthorizeResponseDto = {
    url: string;
 };
 export type OAuthCallbackDto = {
    url: string;
+    state?: string;
+    codeVerifier?: string;
 };
 export type PartnerResponseDto = {
    avatarColor: UserAvatarColor;
--- a/server/package-lock.json
+++ b/server/package-lock.json
@ -52,7 +52,7 @@
        "nestjs-kysely": "^1.1.0",
        "nestjs-otel": "^6.0.0",
        "nodemailer": "^6.9.13",
-        "openid-client": "^5.4.3",
+        "openid-client": "^6.3.3",
        "pg": "^8.11.3",
        "picomatch": "^4.0.2",
        "react": "^19.0.0",
@ -11370,9 +11370,9 @@
      }
    },
    "node_modules/jose": {
-      "version": "4.15.9",
-      "resolved": "https://registry.npmjs.org/jose/-/jose-4.15.9.tgz",
-      "integrity": "sha512-1vUQX+IdDMVPj4k8kOxgUqlcK518yluMuGZwqlr44FS1ppZB/5GWh4rZG89erpOBOJjU/OBsnCVFfapsRz6nEA==",
+      "version": "6.0.8",
+      "resolved": "https://registry.npmjs.org/jose/-/jose-6.0.8.tgz",
+      "integrity": "sha512-EyUPtOKyTYq+iMOszO42eobQllaIjJnwkZ2U93aJzNyPibCy7CEvT9UQnaCVB51IAd49gbNdCew1c0LcLTCB2g==",
      "license": "MIT",
      "funding": {
        "url": "https://github.com/sponsors/panva"
@ -11879,18 +11879,6 @@
      "dev": true,
      "license": "MIT"
    },
-    "node_modules/lru-cache": {
-      "version": "6.0.0",
-      "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-6.0.0.tgz",
-      "integrity": "sha512-Jo6dJ04CmSjuznwJSS3pUeWmd/H0ffTlkXXgwZi+eq1UCmqQwCh+eLsYOYCwY991i2Fah4h1BEMCx4qThGbsiA==",
-      "license": "ISC",
-      "dependencies": {
-        "yallist": "^4.0.0"
-      },
-      "engines": {
-        "node": ">=10"
-      }
-    },
    "node_modules/luxon": {
      "version": "3.6.1",
      "resolved": "https://registry.npmjs.org/luxon/-/luxon-3.6.1.tgz",
@ -12750,6 +12738,14 @@
        "set-blocking": "^2.0.0"
      }
    },
+    "node_modules/oauth4webapi": {
+      "version": "3.3.0",
+      "resolved": "https://registry.npmjs.org/oauth4webapi/-/oauth4webapi-3.3.0.tgz",
+      "integrity": "sha512-ZlozhPlFfobzh3hB72gnBFLjXpugl/dljz1fJSRdqaV2r3D5dmi5lg2QWI0LmUYuazmE+b5exsloEv6toUtw9g==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/panva"
+      }
    "node_modules/nwsapi": {
      "version": "2.2.20",
      "resolved": "https://registry.npmjs.org/nwsapi/-/nwsapi-2.2.20.tgz",
@ -12869,29 +12865,18 @@
      }
    },
    "node_modules/openid-client": {
-      "version": "5.7.1",
-      "resolved": "https://registry.npmjs.org/openid-client/-/openid-client-5.7.1.tgz",
-      "integrity": "sha512-jDBPgSVfTnkIh71Hg9pRvtJc6wTwqjRkN88+gCFtYWrlP4Yx2Dsrow8uPi3qLr/aeymPF3o2+dS+wOpglK04ew==",
+      "version": "6.3.3",
+      "resolved": "https://registry.npmjs.org/openid-client/-/openid-client-6.3.3.tgz",
+      "integrity": "sha512-lTK8AV8SjqCM4qznLX0asVESAwzV39XTVdfMAM185ekuaZCnkWdPzcxMTXNlsm9tsUAMa1Q30MBmKAykdT1LWw==",
      "license": "MIT",
      "dependencies": {
-        "jose": "^4.15.9",
-        "lru-cache": "^6.0.0",
-        "object-hash": "^2.2.0",
-        "oidc-token-hash": "^5.0.3"
+        "jose": "^6.0.6",
+        "oauth4webapi": "^3.3.0"
      },
      "funding": {
        "url": "https://github.com/sponsors/panva"
      }
    },
-    "node_modules/openid-client/node_modules/object-hash": {
-      "version": "2.2.0",
-      "resolved": "https://registry.npmjs.org/object-hash/-/object-hash-2.2.0.tgz",
-      "integrity": "sha512-gScRMn0bS5fH+IuwyIFgnh9zBdo4DV+6GhygmWM9HyNJSgS0hScp1f5vjtm7oIIOiT9trXrShAkLFSc2IqKNgw==",
-      "license": "MIT",
-      "engines": {
-        "node": ">= 6"
-      }
-    },
    "node_modules/optionator": {
      "version": "0.9.4",
      "resolved": "https://registry.npmjs.org/optionator/-/optionator-0.9.4.tgz",
--- a/server/package.json
+++ b/server/package.json
@ -77,7 +77,7 @@
    "nestjs-kysely": "^1.1.0",
    "nestjs-otel": "^6.0.0",
    "nodemailer": "^6.9.13",
-    "openid-client": "^5.4.3",
+    "openid-client": "^6.3.3",
    "pg": "^8.11.3",
    "picomatch": "^4.0.2",
    "react": "^19.0.0",
--- a/server/src/controllers/oauth.controller.ts
+++ b/server/src/controllers/oauth.controller.ts
@ -29,17 +29,35 @@ export class OAuthController {
  }

  @Post('authorize')
-  startOAuth(@Body() dto: OAuthConfigDto): Promise<OAuthAuthorizeResponseDto> {
-    return this.service.authorize(dto);
+  async startOAuth(
+    @Body() dto: OAuthConfigDto,
+    @Res({ passthrough: true }) res: Response,
+    @GetLoginDetails() loginDetails: LoginDetails,
+  ): Promise<OAuthAuthorizeResponseDto> {
+    const { url, state, codeVerifier } = await this.service.authorize(dto);
+    return respondWithCookie(
+      res,
+      { url },
+      {
+        isSecure: loginDetails.isSecure,
+        values: [
+          { key: ImmichCookie.OAUTH_STATE, value: state },
+          { key: ImmichCookie.OAUTH_CODE_VERIFIER, value: codeVerifier },
+        ],
+      },
+    );
  }

  @Post('callback')
  async finishOAuth(
+    @Req() request: Request,
    @Res({ passthrough: true }) res: Response,
    @Body() dto: OAuthCallbackDto,
    @GetLoginDetails() loginDetails: LoginDetails,
  ): Promise<LoginResponseDto> {
-    const body = await this.service.callback(dto, loginDetails);
+    const body = await this.service.callback(dto, request.headers, loginDetails);
+    res.clearCookie(ImmichCookie.OAUTH_STATE);
+    res.clearCookie(ImmichCookie.OAUTH_CODE_VERIFIER);
    return respondWithCookie(res, body, {
      isSecure: loginDetails.isSecure,
      values: [
@ -52,8 +70,12 @@ export class OAuthController {

  @Post('link')
  @Authenticated()
-  linkOAuthAccount(@Auth() auth: AuthDto, @Body() dto: OAuthCallbackDto): Promise<UserAdminResponseDto> {
-    return this.service.link(auth, dto);
+  linkOAuthAccount(
+    @Req() request: Request,
+    @Auth() auth: AuthDto,
+    @Body() dto: OAuthCallbackDto,
+  ): Promise<UserAdminResponseDto> {
+    return this.service.link(auth, dto, request.headers);
  }

  @Post('unlink')
--- a/server/src/dtos/auth.dto.ts
+++ b/server/src/dtos/auth.dto.ts
@ -3,11 +3,11 @@ import { Transform } from 'class-transformer';
 import { IsEmail, IsNotEmpty, IsString, MinLength } from 'class-validator';
 import { AuthApiKey, AuthSession, AuthSharedLink, AuthUser, UserAdmin } from 'src/database';
 import { ImmichCookie } from 'src/enum';
-import { toEmail } from 'src/validation';
+import { Optional, toEmail } from 'src/validation';

 export type CookieResponse = {
  isSecure: boolean;
-  values: Array<{ key: ImmichCookie; value: string }>;
+  values: Array<{ key: ImmichCookie; value: string | null }>;
 };

 export class AuthDto {
@ -87,12 +87,28 @@ export class OAuthCallbackDto {
  @IsString()
  @ApiProperty()
  url!: string;
+
+  @Optional()
+  @IsString()
+  state?: string;
+
+  @Optional()
+  @IsString()
+  codeVerifier?: string;
 }

 export class OAuthConfigDto {
  @IsNotEmpty()
  @IsString()
  redirectUri!: string;
+
+  @Optional()
+  @IsString()
+  state?: string;
+
+  @Optional()
+  @IsString()
+  codeChallenge?: string;
 }

 export class OAuthAuthorizeResponseDto {
--- a/server/src/enum.ts
+++ b/server/src/enum.ts
@ -8,6 +8,8 @@ export enum ImmichCookie {
  AUTH_TYPE = 'immich_auth_type',
  IS_AUTHENTICATED = 'immich_is_authenticated',
  SHARED_LINK_TOKEN = 'immich_shared_link_token',
+  OAUTH_STATE = 'immich_oauth_state',
+  OAUTH_CODE_VERIFIER = 'immich_oauth_code_verifier',
 }

 export enum ImmichHeader {
--- a/server/src/repositories/oauth.repository.ts
+++ b/server/src/repositories/oauth.repository.ts
@ -1,5 +1,5 @@
 import { Injectable, InternalServerErrorException } from '@nestjs/common';
-import { custom, generators, Issuer, UserinfoResponse } from 'openid-client';
+import type { UserInfoResponse } from 'openid-client' with { 'resolution-mode': 'import' };
 import { LoggingRepository } from 'src/repositories/logging.repository';

 export type OAuthConfig = {
@ -12,7 +12,7 @@ export type OAuthConfig = {
  scope: string;
  signingAlgorithm: string;
 };
-export type OAuthProfile = UserinfoResponse;
+export type OAuthProfile = UserInfoResponse;

@Injectable()
 export class OAuthRepository {
@ -20,30 +20,47 @@ export class OAuthRepository {
    this.logger.setContext(OAuthRepository.name);
  }

-  init() {
-    custom.setHttpOptionsDefaults({ timeout: 30_000 });
-  }
-
-  async authorize(config: OAuthConfig, redirectUrl: string) {
+  async authorize(config: OAuthConfig, redirectUrl: string, state?: string, codeChallenge?: string) {
+    const { buildAuthorizationUrl, randomState, randomPKCECodeVerifier, calculatePKCECodeChallenge } = await import(
+      'openid-client'
+    );
    const client = await this.getClient(config);
-    return client.authorizationUrl({
+    state ??= randomState();
+    let codeVerifier: string | null;
+    if (codeChallenge) {
+      codeVerifier = null;
+    } else {
+      codeVerifier = randomPKCECodeVerifier();
+      codeChallenge = await calculatePKCECodeChallenge(codeVerifier);
+    }
+    const url = buildAuthorizationUrl(client, {
      redirect_uri: redirectUrl,
      scope: config.scope,
-      state: generators.state(),
-    });
+      state,
+      code_challenge: codeChallenge,
+      code_challenge_method: 'S256',
+    }).toString();
+    return { url, state, codeVerifier };
  }

  async getLogoutEndpoint(config: OAuthConfig) {
    const client = await this.getClient(config);
-    return client.issuer.metadata.end_session_endpoint;
+    return client.serverMetadata().end_session_endpoint;
  }

-  async getProfile(config: OAuthConfig, url: string, redirectUrl: string): Promise<OAuthProfile> {
+  async getProfile(
+    config: OAuthConfig,
+    url: string,
+    expectedState: string,
+    codeVerifier: string,
+  ): Promise<OAuthProfile> {
+    const { authorizationCodeGrant, fetchUserInfo, ...oidc } = await import('openid-client');
    const client = await this.getClient(config);
-    const params = client.callbackParams(url);
+    const pkceCodeVerifier = client.serverMetadata().supportsPKCE() ? codeVerifier : undefined;
+
    try {
-      const tokens = await client.callback(redirectUrl, params, { state: params.state });
-      const profile = await client.userinfo<OAuthProfile>(tokens.access_token || '');
+      const tokens = await authorizationCodeGrant(client, new URL(url), { expectedState, pkceCodeVerifier });
+      const profile = await fetchUserInfo(client, tokens.access_token, oidc.skipSubjectCheck);
      if (!profile.sub) {
        throw new Error('Unexpected profile response, no `sub`');
      }
@ -59,6 +76,11 @@ export class OAuthRepository {
        );
      }

+      if (error.code === 'OAUTH_INVALID_RESPONSE') {
+        this.logger.warn(`Invalid response from authorization server. Cause: ${error.cause?.message}`);
+        throw error.cause;
+      }
+
      throw error;
    }
  }
@ -83,14 +105,20 @@ export class OAuthRepository {
    signingAlgorithm,
  }: OAuthConfig) {
    try {
-      const issuer = await Issuer.discover(issuerUrl);
-      return new issuer.Client({
-        client_id: clientId,
-        client_secret: clientSecret,
-        response_types: ['code'],
-        userinfo_signed_response_alg: profileSigningAlgorithm === 'none' ? undefined : profileSigningAlgorithm,
-        id_token_signed_response_alg: signingAlgorithm,
-      });
+      const { allowInsecureRequests, discovery } = await import('openid-client');
+      return await discovery(
+        new URL(issuerUrl),
+        clientId,
+        {
+          client_secret: clientSecret,
+          response_types: ['code'],
+          userinfo_signed_response_alg: profileSigningAlgorithm === 'none' ? undefined : profileSigningAlgorithm,
+          id_token_signed_response_alg: signingAlgorithm,
+          timeout: 30_000,
+        },
+        undefined,
+        { execute: [allowInsecureRequests] },
+      );
    } catch (error: any | AggregateError) {
      this.logger.error(`Error in OAuth discovery: ${error}`, error?.stack, error?.errors);
      throw new InternalServerErrorException(`Error in OAuth discovery: ${error}`, { cause: error });
--- a/server/src/services/auth.service.spec.ts
+++ b/server/src/services/auth.service.spec.ts
@ -55,7 +55,7 @@ describe(AuthService.name, () => {
  beforeEach(() => {
    ({ sut, mocks } = newTestService(AuthService));

-    mocks.oauth.authorize.mockResolvedValue('access-token');
+    mocks.oauth.authorize.mockResolvedValue({ url: 'http://test', state: 'state', codeVerifier: 'codeVerifier' });
    mocks.oauth.getProfile.mockResolvedValue({ sub, email });
    mocks.oauth.getLogoutEndpoint.mockResolvedValue('http://end-session-endpoint');
  });
@ -64,16 +64,6 @@ describe(AuthService.name, () => {
    expect(sut).toBeDefined();
  });

-  describe('onBootstrap', () => {
-    it('should init the repo', () => {
-      mocks.oauth.init.mockResolvedValue();
-
-      sut.onBootstrap();
-
-      expect(mocks.oauth.init).toHaveBeenCalled();
-    });
-  });
-
  describe('login', () => {
    it('should throw an error if password login is disabled', async () => {
      mocks.systemMetadata.get.mockResolvedValue(systemConfigStub.disabled);
@ -519,16 +509,22 @@ describe(AuthService.name, () => {

  describe('callback', () => {
    it('should throw an error if OAuth is not enabled', async () => {
-      await expect(sut.callback({ url: '' }, loginDetails)).rejects.toBeInstanceOf(BadRequestException);
+      await expect(
+        sut.callback({ url: '', state: 'xyz789', codeVerifier: 'foo' }, {}, loginDetails),
+      ).rejects.toBeInstanceOf(BadRequestException);
    });

    it('should not allow auto registering', async () => {
      mocks.systemMetadata.get.mockResolvedValue(systemConfigStub.oauthEnabled);
      mocks.user.getByEmail.mockResolvedValue(void 0);

-      await expect(sut.callback({ url: 'http://immich/auth/login?code=abc123' }, loginDetails)).rejects.toBeInstanceOf(
-        BadRequestException,
-      );
+      await expect(
+        sut.callback(
+          { url: 'http://immich/auth/login?code=abc123', state: 'xyz789', codeVerifier: 'foo' },
+          {},
+          loginDetails,
+        ),
+      ).rejects.toBeInstanceOf(BadRequestException);

      expect(mocks.user.getByEmail).toHaveBeenCalledTimes(1);
    });
@ -541,9 +537,13 @@ describe(AuthService.name, () => {
      mocks.user.update.mockResolvedValue(user);
      mocks.session.create.mockResolvedValue(factory.session());

-      await expect(sut.callback({ url: 'http://immich/auth/login?code=abc123' }, loginDetails)).resolves.toEqual(
-        oauthResponse(user),
-      );
+      await expect(
+        sut.callback(
+          { url: 'http://immich/auth/login?code=abc123', state: 'xyz789', codeVerifier: 'foobar' },
+          {},
+          loginDetails,
+        ),
+      ).resolves.toEqual(oauthResponse(user));

      expect(mocks.user.getByEmail).toHaveBeenCalledTimes(1);
      expect(mocks.user.update).toHaveBeenCalledWith(user.id, { oauthId: sub });
@ -557,9 +557,13 @@ describe(AuthService.name, () => {
      mocks.user.getAdmin.mockResolvedValue(user);
      mocks.user.create.mockResolvedValue(user);

-      await expect(sut.callback({ url: 'http://immich/auth/login?code=abc123' }, loginDetails)).rejects.toThrow(
-        BadRequestException,
-      );
+      await expect(
+        sut.callback(
+          { url: 'http://immich/auth/login?code=abc123', state: 'xyz789', codeVerifier: 'foobar' },
+          {},
+          loginDetails,
+        ),
+      ).rejects.toThrow(BadRequestException);

      expect(mocks.user.update).not.toHaveBeenCalled();
      expect(mocks.user.create).not.toHaveBeenCalled();
@ -574,9 +578,13 @@ describe(AuthService.name, () => {
      mocks.user.create.mockResolvedValue(user);
      mocks.session.create.mockResolvedValue(factory.session());

-      await expect(sut.callback({ url: 'http://immich/auth/login?code=abc123' }, loginDetails)).resolves.toEqual(
-        oauthResponse(user),
-      );
+      await expect(
+        sut.callback(
+          { url: 'http://immich/auth/login?code=abc123', state: 'xyz789', codeVerifier: 'foobar' },
+          {},
+          loginDetails,
+        ),
+      ).resolves.toEqual(oauthResponse(user));

      expect(mocks.user.getByEmail).toHaveBeenCalledTimes(2); // second call is for domain check before create
      expect(mocks.user.create).toHaveBeenCalledTimes(1);
@ -592,18 +600,19 @@ describe(AuthService.name, () => {
      mocks.session.create.mockResolvedValue(factory.session());
      mocks.oauth.getProfile.mockResolvedValue({ sub, email: undefined });

-      await expect(sut.callback({ url: 'http://immich/auth/login?code=abc123' }, loginDetails)).rejects.toBeInstanceOf(
-        BadRequestException,
-      );
+      await expect(
+        sut.callback(
+          { url: 'http://immich/auth/login?code=abc123', state: 'xyz789', codeVerifier: 'foobar' },
+          {},
+          loginDetails,
+        ),
+      ).rejects.toBeInstanceOf(BadRequestException);

      expect(mocks.user.getByEmail).not.toHaveBeenCalled();
      expect(mocks.user.create).not.toHaveBeenCalled();
    });

    for (const url of [
-      'app.immich:/',
-      'app.immich://',
-      'app.immich:///',
      'app.immich:/oauth-callback?code=abc123',
      'app.immich://oauth-callback?code=abc123',
      'app.immich:///oauth-callback?code=abc123',
@ -615,9 +624,14 @@ describe(AuthService.name, () => {
        mocks.user.getByOAuthId.mockResolvedValue(user);
        mocks.session.create.mockResolvedValue(factory.session());

-        await sut.callback({ url }, loginDetails);
+        await sut.callback({ url, state: 'xyz789', codeVerifier: 'foo' }, {}, loginDetails);

-        expect(mocks.oauth.getProfile).toHaveBeenCalledWith(expect.objectContaining({}), url, 'http://mobile-redirect');
+        expect(mocks.oauth.getProfile).toHaveBeenCalledWith(
+          expect.objectContaining({}),
+          'http://mobile-redirect?code=abc123',
+          'xyz789',
+          'foo',
+        );
      });
    }

@ -630,9 +644,13 @@ describe(AuthService.name, () => {
      mocks.user.create.mockResolvedValue(user);
      mocks.session.create.mockResolvedValue(factory.session());

-      await expect(sut.callback({ url: 'http://immich/auth/login?code=abc123' }, loginDetails)).resolves.toEqual(
-        oauthResponse(user),
-      );
+      await expect(
+        sut.callback(
+          { url: 'http://immich/auth/login?code=abc123', state: 'xyz789', codeVerifier: 'foo' },
+          {},
+          loginDetails,
+        ),
+      ).resolves.toEqual(oauthResponse(user));

      expect(mocks.user.create).toHaveBeenCalledWith(expect.objectContaining({ quotaSizeInBytes: 1_073_741_824 }));
    });
@ -647,9 +665,13 @@ describe(AuthService.name, () => {
      mocks.user.create.mockResolvedValue(user);
      mocks.session.create.mockResolvedValue(factory.session());

-      await expect(sut.callback({ url: 'http://immich/auth/login?code=abc123' }, loginDetails)).resolves.toEqual(
-        oauthResponse(user),
-      );
+      await expect(
+        sut.callback(
+          { url: 'http://immich/auth/login?code=abc123', state: 'xyz789', codeVerifier: 'foo' },
+          {},
+          loginDetails,
+        ),
+      ).resolves.toEqual(oauthResponse(user));

      expect(mocks.user.create).toHaveBeenCalledWith(expect.objectContaining({ quotaSizeInBytes: 1_073_741_824 }));
    });
@ -664,9 +686,13 @@ describe(AuthService.name, () => {
      mocks.user.create.mockResolvedValue(user);
      mocks.session.create.mockResolvedValue(factory.session());

-      await expect(sut.callback({ url: 'http://immich/auth/login?code=abc123' }, loginDetails)).resolves.toEqual(
-        oauthResponse(user),
-      );
+      await expect(
+        sut.callback(
+          { url: 'http://immich/auth/login?code=abc123', state: 'xyz789', codeVerifier: 'foo' },
+          {},
+          loginDetails,
+        ),
+      ).resolves.toEqual(oauthResponse(user));

      expect(mocks.user.create).toHaveBeenCalledWith(expect.objectContaining({ quotaSizeInBytes: 1_073_741_824 }));
    });
@ -681,9 +707,13 @@ describe(AuthService.name, () => {
      mocks.user.create.mockResolvedValue(user);
      mocks.session.create.mockResolvedValue(factory.session());

-      await expect(sut.callback({ url: 'http://immich/auth/login?code=abc123' }, loginDetails)).resolves.toEqual(
-        oauthResponse(user),
-      );
+      await expect(
+        sut.callback(
+          { url: 'http://immich/auth/login?code=abc123', state: 'xyz789', codeVerifier: 'foo' },
+          {},
+          loginDetails,
+        ),
+      ).resolves.toEqual(oauthResponse(user));

      expect(mocks.user.create).toHaveBeenCalledWith({
        email: user.email,
@ -705,9 +735,13 @@ describe(AuthService.name, () => {
      mocks.user.create.mockResolvedValue(user);
      mocks.session.create.mockResolvedValue(factory.session());

-      await expect(sut.callback({ url: 'http://immich/auth/login?code=abc123' }, loginDetails)).resolves.toEqual(
-        oauthResponse(user),
-      );
+      await expect(
+        sut.callback(
+          { url: 'http://immich/auth/login?code=abc123', state: 'xyz789', codeVerifier: 'foo' },
+          {},
+          loginDetails,
+        ),
+      ).resolves.toEqual(oauthResponse(user));

      expect(mocks.user.create).toHaveBeenCalledWith({
        email: user.email,
@ -779,7 +813,11 @@ describe(AuthService.name, () => {
      mocks.systemMetadata.get.mockResolvedValue(systemConfigStub.enabled);
      mocks.user.update.mockResolvedValue(user);

-      await sut.link(auth, { url: 'http://immich/user-settings?code=abc123' });
+      await sut.link(
+        auth,
+        { url: 'http://immich/user-settings?code=abc123', state: 'xyz789', codeVerifier: 'foo' },
+        {},
+      );

      expect(mocks.user.update).toHaveBeenCalledWith(auth.user.id, { oauthId: sub });
    });
@ -792,9 +830,9 @@ describe(AuthService.name, () => {
      mocks.systemMetadata.get.mockResolvedValue(systemConfigStub.enabled);
      mocks.user.getByOAuthId.mockResolvedValue({ id: 'other-user' } as UserAdmin);

-      await expect(sut.link(auth, { url: 'http://immich/user-settings?code=abc123' })).rejects.toBeInstanceOf(
-        BadRequestException,
-      );
+      await expect(
+        sut.link(auth, { url: 'http://immich/user-settings?code=abc123', state: 'xyz789', codeVerifier: 'foo' }, {}),
+      ).rejects.toBeInstanceOf(BadRequestException);

      expect(mocks.user.update).not.toHaveBeenCalled();
    });
--- a/server/src/services/auth.service.ts
+++ b/server/src/services/auth.service.ts
@ -7,13 +7,11 @@ import { join } from 'node:path';
 import { LOGIN_URL, MOBILE_REDIRECT, SALT_ROUNDS } from 'src/constants';
 import { StorageCore } from 'src/cores/storage.core';
 import { UserAdmin } from 'src/database';
-import { OnEvent } from 'src/decorators';
 import {
  AuthDto,
  ChangePasswordDto,
  LoginCredentialDto,
  LogoutResponseDto,
-  OAuthAuthorizeResponseDto,
  OAuthCallbackDto,
  OAuthConfigDto,
  SignUpDto,
@ -52,11 +50,6 @@ export type ValidateRequest = {

@Injectable()
 export class AuthService extends BaseService {
-  @OnEvent({ name: 'app.bootstrap' })
-  onBootstrap() {
-    this.oauthRepository.init();
-  }
-
  async login(dto: LoginCredentialDto, details: LoginDetails) {
    const config = await this.getConfig({ withCache: false });
    if (!config.passwordLogin.enabled) {
@ -176,20 +169,35 @@ export class AuthService extends BaseService {
    return `${MOBILE_REDIRECT}?${url.split('?')[1] || ''}`;
  }

-  async authorize(dto: OAuthConfigDto): Promise<OAuthAuthorizeResponseDto> {
+  async authorize(dto: OAuthConfigDto) {
    const { oauth } = await this.getConfig({ withCache: false });

    if (!oauth.enabled) {
      throw new BadRequestException('OAuth is not enabled');
    }

-    const url = await this.oauthRepository.authorize(oauth, this.resolveRedirectUri(oauth, dto.redirectUri));
-    return { url };
+    return await this.oauthRepository.authorize(
+      oauth,
+      this.resolveRedirectUri(oauth, dto.redirectUri),
+      dto.state,
+      dto.codeChallenge,
+    );
  }

-  async callback(dto: OAuthCallbackDto, loginDetails: LoginDetails) {
+  async callback(dto: OAuthCallbackDto, headers: IncomingHttpHeaders, loginDetails: LoginDetails) {
+    const expectedState = dto.state ?? this.getCookieOauthState(headers);
+    if (!expectedState?.length) {
+      throw new BadRequestException('OAuth state is missing');
+    }
+
+    const codeVerifier = dto.codeVerifier ?? this.getCookieCodeVerifier(headers);
+    if (!codeVerifier?.length) {
+      throw new BadRequestException('OAuth code verifier is missing');
+    }
+
    const { oauth } = await this.getConfig({ withCache: false });
-    const profile = await this.oauthRepository.getProfile(oauth, dto.url, this.resolveRedirectUri(oauth, dto.url));
+    const url = this.resolveRedirectUri(oauth, dto.url);
+    const profile = await this.oauthRepository.getProfile(oauth, url, expectedState, codeVerifier);
    const { autoRegister, defaultStorageQuota, storageLabelClaim, storageQuotaClaim } = oauth;
    this.logger.debug(`Logging in with OAuth: ${JSON.stringify(profile)}`);
    let user: UserAdmin | undefined = await this.userRepository.getByOAuthId(profile.sub);
@ -271,13 +279,19 @@ export class AuthService extends BaseService {
    }
  }

-  async link(auth: AuthDto, dto: OAuthCallbackDto): Promise<UserAdminResponseDto> {
+  async link(auth: AuthDto, dto: OAuthCallbackDto, headers: IncomingHttpHeaders): Promise<UserAdminResponseDto> {
+    const expectedState = dto.state ?? this.getCookieOauthState(headers);
+    if (!expectedState?.length) {
+      throw new BadRequestException('OAuth state is missing');
+    }
+
+    const codeVerifier = dto.codeVerifier ?? this.getCookieCodeVerifier(headers);
+    if (!codeVerifier?.length) {
+      throw new BadRequestException('OAuth code verifier is missing');
+    }
+
    const { oauth } = await this.getConfig({ withCache: false });
-    const { sub: oauthId } = await this.oauthRepository.getProfile(
-      oauth,
-      dto.url,
-      this.resolveRedirectUri(oauth, dto.url),
-    );
+    const { sub: oauthId } = await this.oauthRepository.getProfile(oauth, dto.url, expectedState, codeVerifier);
    const duplicate = await this.userRepository.getByOAuthId(oauthId);
    if (duplicate && duplicate.id !== auth.user.id) {
      this.logger.warn(`OAuth link account failed: sub is already linked to another user (${duplicate.email}).`);
@ -320,6 +334,16 @@ export class AuthService extends BaseService {
    return cookies[ImmichCookie.ACCESS_TOKEN] || null;
  }

+  private getCookieOauthState(headers: IncomingHttpHeaders): string | null {
+    const cookies = parse(headers.cookie || '');
+    return cookies[ImmichCookie.OAUTH_STATE] || null;
+  }
+
+  private getCookieCodeVerifier(headers: IncomingHttpHeaders): string | null {
+    const cookies = parse(headers.cookie || '');
+    return cookies[ImmichCookie.OAUTH_CODE_VERIFIER] || null;
+  }
+
  async validateSharedLink(key: string | string[]): Promise<AuthDto> {
    key = Array.isArray(key) ? key[0] : key;

@ -399,11 +423,9 @@ export class AuthService extends BaseService {
    { mobileRedirectUri, mobileOverrideEnabled }: { mobileRedirectUri: string; mobileOverrideEnabled: boolean },
    url: string,
  ) {
-    const redirectUri = url.split('?')[0];
-    const isMobile = redirectUri.startsWith('app.immich:/');
-    if (isMobile && mobileOverrideEnabled && mobileRedirectUri) {
-      return mobileRedirectUri;
+    if (mobileOverrideEnabled && mobileRedirectUri) {
+      return url.replace(/app\.immich:\/+oauth-callback/, mobileRedirectUri);
    }
-    return redirectUri;
+    return url;
  }
 }
--- a/server/src/utils/response.ts
+++ b/server/src/utils/response.ts
@ -15,6 +15,8 @@ export const respondWithCookie = <T>(res: Response, body: T, { isSecure, values
  const cookieOptions: Record<ImmichCookie, CookieOptions> = {
    [ImmichCookie.AUTH_TYPE]: defaults,
    [ImmichCookie.ACCESS_TOKEN]: defaults,
+    [ImmichCookie.OAUTH_STATE]: defaults,
+    [ImmichCookie.OAUTH_CODE_VERIFIER]: defaults,
    // no httpOnly so that the client can know the auth state
    [ImmichCookie.IS_AUTHENTICATED]: { ...defaults, httpOnly: false },
    [ImmichCookie.SHARED_LINK_TOKEN]: { ...defaults, maxAge: Duration.fromObject({ days: 1 }).toMillis() },