EUVD Vulnerability Catalog
EUVD-2026-72782
Severity: CRITICAL
Base Score: 9.1
CVSS Version: 4.0
Vulnerability Description
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 Vector Analysis
Below is the complete, human-readable breakdown of the CVSS metric string: 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
▪
Attack Vector (AV): Network
▪
Attack Complexity (AC): High
▪
Attack Requirements (AT): None
▪
Privileges Required (PR): None
▪
User Interaction (UI): None
▪
Vulnerability Confidentiality Impact (VC): High
▪
Vulnerability Integrity Impact (VI): High
▪
Vulnerability Availability Impact (VA): None
▪
Subsequent Confidentiality Impact (SC): None
▪
Subsequent Integrity Impact (SI): None
▪
Subsequent Availability Impact (SA): None
Affected Vendors & Systems
Vendor
Xenforo
References & Advisory Links
- 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/
- 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
Metadata Profile
Database Authority
European Union Agency for Cybersecurity (ENISA) EUVD
Assigner
VulnCheck
EPSS Probability
0
Known Aliases
CVE-2026-73311
GHSA-mrq5-6m75-wpj5
Published On
2026-09-08
Last Updated
2026-09-09