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TI-2026-51436 Aliases CVE-2026-73311GHSA-mrq5-6m75-wpj5

XenForo < 2.3.13 OAuth2 Authorization Code Reuse

Priority HIGH 74CWE-294Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-294.

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00498 42nd percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD and the CNA
Fix Fixed XenForo (XenForo): 2.3.13

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
XenForoXenForobefore 2.3.132.3.13Patch availableCNA
  • XenForo VendorXenForo Affected before 2.3.13 Fixed in 2.3.13 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:xenforo:xenforo:*:*:*:*:*:*:*:*before 2.3.13VulnerableXenForo
  • cpe:2.3:a:xenforo:xenforo:*:*:*:*:*:*:*:* Versions before 2.3.13 Vulnerable ·XenForo

Remediation

  • Fix · CNA XenForo (XenForo) Fixed in 2.3.13

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    XenForo — xenforo.com/community/threads/security-fixes-released-for-a…

    14 records Highest priority Priority HIGH 4 HIGH, 5 MEDIUM, 5 LOW

    Other records, highest priority first

    • TI-2026-51441 XenForo < 2.3.13 Payment Replay via PayPal REST Payment ProviderPriority HIGH 77
    • TI-2026-51439 XenForo < 2.3.13 Signature Verification Bypass via PayPal REST WebhookPriority HIGH 77
    • TI-2026-51434 XenForo < 2.3.13 Authentication Bypass via OAuth2 Token EndpointPriority HIGH 74
    Show all 14 records → Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-73311
  2. 2026-10-03 Alias added: GHSA-mrq5-6m75-wpj5

References

Exploit 2

Patch 1

Other 1

  • TI-2026-51441 XenForo < 2.3.13 Payment Replay via PayPal REST Payment Provider CVSS 4.0HIGH 8.7
  • TI-2026-51439 XenForo < 2.3.13 Signature Verification Bypass via PayPal REST Webhook CVSS 4.0HIGH 8.7
  • TI-2026-51434 XenForo < 2.3.13 Authentication Bypass via OAuth2 Token Endpoint CVSS 4.0CRITICAL 9.1
  • TI-2024-25701 Xenforo before 2.2.16 allows code injection. CVSS 3.1HIGH 8.8
  • TI-2026-51446 XenForo < 2.3.13 Uncontrolled Recursion DoS via BBCode Parser CVSS 4.0HIGH 7.1
  • TI-2026-51444 XenForo < 2.3.13 XSS via Dynamic Redirect Handler CVSS 4.0MEDIUM 5.1
See all 27 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences