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)
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.004 (28.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 28.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- Vendor Advisory (vendor-advisory, patch, Release Notes)
- Release Notes (release-notes, Release Notes)
- www.vulncheck.com/advisories/xenforo-unauthenticated-information-disclosure-via… (Third Party Advisory, third-party-advisory)
- Researcher Advisory (Exploit, technical-description, Third Party Advisory)
- Researcher PoC (Exploit, exploit, Third Party Advisory)
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.