XenForo < 2.3.13 OAuth2 Authorization Code Reuse
48Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 9.1epss 0.4%
exploitation probability
0.4%top 69% of all CVEs
observed exploitation
nono source reports it
1 public exploit(s)
XenForo before 2.3.13 contains an OAuth2 authorization code reuse vulnerability that allows attackers to obtain unauthorized token pairs by submitting a previously used authorization code. Attackers can exploit the failure to invalidate or mark authorization codes as consumed after initial token issuance to receive an independent token pair for the same user and scopes, bypassing the single-use guarantee of the OAuth2 authorization code flow.
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
Affected products
XenForo · XenForopublic PoCs found — 1
cve_referencegithub.com/BomboBombone/CVE-2026-73311★ 0⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
References
https://bombobombone.github.io/posts/cve-2026-73311/https://github.com/BomboBombone/CVE-2026-73311https://www.vulncheck.com/advisories/xenforo-oauth2-authorization-code-reusehttps://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/