{"id":"GHSA-349c-2h2f-mxf6","summary":"Laravel Passport: TokenGuard Authenticates Unrelated User for Client Credentials Tokens","details":"### Impact\nAuthentication Bypass for `client_credentials` tokens. the league/oauth2-server library sets the JWT sub claim to the client identifier (since there's no user). The token guard then passes this value to retrieveById() without validating it's actually a user identifier, potentially resolving an unrelated real user. Any machine-to-machine token can inadvertently authenticate as an actual user.\n\n\nUsage of `EnsureClientIsResourceOwner` middleware together with `Passport::$clientUuids` set to `false`, can result in resolving the user instead, as stated in the [documentation](https://laravel.com/docs/13.x/passport#:~:text=The%20underlying%20OAuth2,client%20credentials%20token). \n\n\u003e The [underlying OAuth2 server](https://oauth2.thephpleague.com/database-setup/#:~:text=Please%20note%20that,the%20bearer%20token.) sets the token's sub claim to the client's identifier for client credentials tokens. By default, Passport uses UUIDs for clients, so this cannot collide with a user's integer primary key. However, if you have set Passport::$clientUuids to false, a client credentials token may inadvertently resolve a user whose ID matches the client's ID. In such cases, using this middleware cannot guarantee that the incoming token is a client credentials token.\n\n### Patches\nPatched in v13.7.1\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\nDisallow usage of `client_credentials`. \n\n\n### References\n- https://github.com/laravel/passport/issues/1900\n- https://github.com/laravel/passport/pull/1901\n- https://github.com/laravel/passport/pull/1902\n- https://github.com/thephpleague/oauth2-server/issues/1456#issuecomment-2734989996","aliases":["CVE-2026-39976"],"modified":"2026-04-13T18:11:23.408579Z","published":"2026-04-08T19:57:55Z","database_specific":{"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-04-08T19:57:55Z","nvd_published_at":"2026-04-09T17:16:31Z","cwe_ids":["CWE-287"]},"references":[{"type":"WEB","url":"https://github.com/laravel/passport/security/advisories/GHSA-349c-2h2f-mxf6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-39976"},{"type":"WEB","url":"https://github.com/laravel/passport/issues/1900"},{"type":"WEB","url":"https://github.com/thephpleague/oauth2-server/issues/1456#issuecomment-2734989996"},{"type":"WEB","url":"https://github.com/laravel/passport/pull/1901"},{"type":"WEB","url":"https://github.com/laravel/passport/pull/1902"},{"type":"PACKAGE","url":"https://github.com/laravel/passport"}],"affected":[{"package":{"name":"laravel/passport","ecosystem":"Packagist","purl":"pkg:composer/laravel/passport"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"13.0.0"},{"fixed":"13.7.1"}]}],"versions":["v13.0.0","v13.0.1","v13.0.2","v13.0.3","v13.0.4","v13.0.5","v13.0.6","v13.1.0","v13.2.0","v13.2.1","v13.2.2","v13.3.0","v13.4.0","v13.4.1","v13.4.2","v13.4.3","v13.4.4","v13.5.0","v13.6.0","v13.7.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-349c-2h2f-mxf6/GHSA-349c-2h2f-mxf6.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N"}]}