CVE-2026-73309: falha crítica em XenForo
XenForo < 2.3.13 Authentication Bypass via OAuth2 Token Endpoint
Publicada em · Atualizada em
Aviso por e-mail quando ela entrar no KEV, ganhar PoC pública ou subir de nota.
48Vexday Risk Score
Sem sinal de exploração. Ela tem prova de conceito pública.
ssvc Attendcvss 9.1epss 0.7%
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.
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Produtos afetados
XenForo · XenForoPoCs públicas encontradas — 1
cve_referencegithub.com/BomboBombone/CVE-2026-73309★ 1⚠ Recursos públicos, para você avaliar a exposição de sistemas que controla ou está autorizado a testar. Teste apenas com autorização.
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Referências
https://bombobombone.github.io/posts/cve-2026-73309/https://github.com/BomboBombone/CVE-2026-73309https://www.vulncheck.com/advisories/xenforo-authentication-bypass-via-oauth2-token-endpointhttps://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/