CVE-2026-73311
highpriority · track · 40OT risk · elevatedEPSS 0.005 · 42 %ileexploit · PoCUSEPSS · scored 2026-10-27
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.4–9.1
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
exploits (1)
Public proof-of-concept and weaponised exploit code.
affected products (1)
Products and version ranges known to be affected.
sources
Which sources assert this record, and when.
references (5) nvd
External citations — patches, advisories, analysis.
- https://bombobombone.github.io/posts/cve-2026-73311/ExploitThird Party Advisory
- https://github.com/BomboBombone/CVE-2026-73311ExploitThird Party Advisory
- https://www.vulncheck.com/advisories/xenforo-oauth2-authorization-code-reuseThird Party Advisory
- https://xenforo.com/community/threads/security-fixes-released-for-all-xenforo-and-media-gallery-versions-2-2-0-2-3-12.239856/Release Notes
- https://xenforo.com/community/threads/xenforo-2-3-13-and-add-ons-released-includes-security-fixes.239857/Release Notes
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