CVE-2026-73311
XenForo < 2.3.13 OAuth2 Authorization Code Reuse
- State
- Published
- Severity
- 9.1 Critical
- Published
- Sep 8, 2026
- Updated
- Oct 1, 2026
- Reserved
- Aug 11, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.1 Critical | 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 | VulnCheck |
| 3.1 | 7.4 High | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N | VulnCheck |
Weaknesses
- CWE-294 Authentication Bypass by Capture-replay
Affected Products
| Product | Versions |
|---|---|
XenForoXenForo |
|
References
- Vendor Advisoryvendor-advisorypatch
- Release Notesrelease-notes
- Researcher Advisorytechnical-description
- Researcher PoCexploit
- https://www.vulncheck.com/advisories/xenforo-oauth2-authorization-code-reusethird-party-advisory
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.