CVE-2026-73310
XenForo < 2.3.13 OAuth2 Authorization Code Token Theft via redirect_uri Bypass
CVSS Score
5.9
EPSS Score
0.0%
EPSS Percentile
0th
XenForo before 2.3.13 contains an authorization flaw in the OAuth2 token endpoint that allows attackers controlling any allowlisted redirect URI to bypass redirect URI binding by submitting a different allowlisted URI than the one recorded at authorization time. Attackers can exchange an intercepted authorization code using a mismatched redirect URI to steal OAuth2 tokens from intercepted authorization flows.
| CWE | CWE-863 |
| Vendor | xenforo |
| Product | xenforo |
| Published | Sep 8, 2026 |
| Last Updated | Sep 9, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Affected Versions
XenForo / XenForo
0 < 2.3.13
References
xenforo.com: https://xenforo.com/community/threads/security-fixes-released-for-all-xenforo-and-media-gallery-versions-2-2-0-2-3-12.239856/ xenforo.com: https://xenforo.com/community/threads/xenforo-2-3-13-and-add-ons-released-includes-security-fixes.239857/ bombobombone.github.io: https://bombobombone.github.io/posts/cve-2026-73310/ github.com: https://github.com/BomboBombone/CVE-2026-73310 vulncheck.com: https://www.vulncheck.com/advisories/xenforo-oauth2-authorization-code-token-theft-via-redirect-uri-bypass
Credits
Marco Paciaroni (BomboBombone) VulnCheck