CVE-2026-39976 — Laravel Passport's TokenGuard Authenticates Unrelated User for Client Credentials Tokens
Laravel Passport provides OAuth2 server support to Laravel. From 13.0.0 to before 13.7.1, there is an Authentication Bypass for client_credentials tokens. the league/oauth2-serv…
Published: 2026-04-09 · CVSS: 7.1 · CVSS 3.1
Laravel Passport provides OAuth2 server support to Laravel. From 13.0.0 to before 13.7.1, there is an Authentication 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. This vulnerability is fixed in 13.7.1.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7