CVE-2026-73309
Gravedad CVSS v4.0:
CRÍTICA
Tipo:
No Disponible / Otro tipo
Fecha de publicación:
08/09/2026
Última modificación:
09/09/2026
Descripción
*** Pendiente de traducción *** XenForo before 2.3.13 contains an authentication bypass vulnerability in the OAuth2 token endpoint that allows unauthenticated attackers to obtain valid token pairs by submitting empty values for client_secret and code_verifier parameters. Attackers can exploit PHP truthy evaluation logic, which treats empty strings as false and skips client secret validation and PKCE code verifier validation, to exchange a valid authorization code for a token pair without proving client identity or holding the PKCE commitment.
Impacto
Puntuación base 4.0
9.10
Gravedad 4.0
CRÍTICA
Puntuación base 3.x
7.40
Gravedad 3.x
ALTA
Referencias a soluciones, herramientas e información
- https://bombobombone.github.io/posts/cve-2026-73309/
- https://github.com/BomboBombone/CVE-2026-73309
- https://www.vulncheck.com/advisories/xenforo-authentication-bypass-via-oauth2-token-endpoint
- https://xenforo.com/community/threads/security-fixes-released-for-all-xenforo-and-media-gallery-versions-2-2-0-2-3-12.239856/
- https://xenforo.com/community/threads/xenforo-2-3-13-and-add-ons-released-includes-security-fixes.239857/