CVE-2026-73311 json
XenForo < 2.3.13 OAuth2 Authorization Code Reuse
published 2026-09-08 2 mo ago modified 2026-10-01 39 d ago also EUVD-2026-72782
- cvss
- 7.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 42%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- XenForo XenForo 2.3.13
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 1 mo ago
Exploit prediction
0.50% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/BomboBombone/CVE-2026-73311 referenced PoC, tagged "exploit" by a source, unverified
- bombobombone.github.io https://bombobombone.github.io/posts/cve-2026-73311/ referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 9.1 | 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 |
| CNA | 3.1 | 7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| CNA | 4.0 | 9.1 | 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 |
Affected products
- XenForo XenForo
Classification
- Weakness
-
- CWE-294 Authentication Bypass by Capture-replay
References
-
xenforo.com
/community/threads/security-fixes-released-for-all-xenforo-and-media-gallery-versions-2-2-0-2-3-12.239856/
vendor-advisory, patch, release-notes
-
github.com
/BomboBombone/CVE-2026-73311
exploit, third-party-advisory
-
bombobombone.github.io
/posts/cve-2026-73311/
technical-description, exploit, third-party-advisory
-
xenforo.com
/community/threads/xenforo-2-3-13-and-add-ons-released-includes-security-fixes.239857/
release-notes
-
vulncheck.com
/advisories/xenforo-oauth2-authorization-code-reuse
third-party-advisory
Sources
- CVE List CVE-2026-73311
- NVD CVE-2026-73311
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.