CVE-2026-73311
critical · 9.1XenForo 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.
9.1
CVSS
0.5%
EPSS (exploit prob.)
42nd
EPSS percentile
2026-09-08
Published
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weaknesses
CWE-294
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| xenforo | xenforo | < 2.3.13 |
Check a specific version with /api/v1/cve/match.
References
- https://bombobombone.github.io/posts/cve-2026-73311/
- https://github.com/BomboBombone/CVE-2026-73311
- https://www.vulncheck.com/advisories/xenforo-oauth2-authorization-code-reuse
- 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/
Query this programmatically:
curl https://evil-db.io/api/v1/cve/CVE-2026-73311