CVE-2026-73311
XenForo < 2.3.13 OAuth2 Authorization Code Reuse
CVSS Score
7.4
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-294 |
| Vendor | xenforo |
| Product | xenforo |
| Published | Sep 8, 2026 |
| Last Updated | Sep 10, 2026 |
Stay Ahead of the Next One
Get instant alerts for xenforo xenforo
Be the first to know when new high vulnerabilities affecting xenforo xenforo are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
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-2026-73311/ github.com: https://github.com/BomboBombone/CVE-2026-73311 vulncheck.com: https://www.vulncheck.com/advisories/xenforo-oauth2-authorization-code-reuse
Credits
Marco Paciaroni (BomboBombone) VulnCheck