Auth bypass in Xenforo
CVE-2026-73320
XenForo before 2.3.13 contains an unauthenticated information disclosure vulnerability that allows unauthenticated attackers to retrieve private unfurl records by supplying predictable auto-increment primary key IDs to the unfurl endpoint. Attackers can enumerate or predict result IDs and query the endpoint without any session, user, or visibility checks to obtain rendered preview HTML, original URLs, and query strings from private conversations and other restricted content.
Vulnerability class: IDOR (Insecure Direct Object Reference)
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- disclosure@vulncheck.com (vendor-advisory, patch)
- disclosure@vulncheck.com (release-notes)
- disclosure@vulncheck.com (third-party-advisory)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (exploit)
Frequently asked questions
- What is CVE-2026-73320?
- CVE-2026-73320 is a medium-severity vulnerability in Xenforo, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 6.1/10. Published 2026-09-08.
- How severe is CVE-2026-73320?
- Medium severity. CVSS v3 base score is 6.1 out of 10.
- Is CVE-2026-73320 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.