XSS in Xenforo
CVE-2026-35054
XenForo before 2.3.9 is vulnerable to stored cross-site scripting (XSS) related to BB code rendering. An attacker can inject malicious scripts through BB code that are stored and executed when other users view the content.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (13.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 13th percentile — 13.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001
Affected products
- Xenforo — versions 2.3.0
Weakness classification (CWE)
References
- xenforo.com/community/threads/xenforo-2-3-9-inc-xfmg-2-2-18-released-security-f… (vendor-advisory, Release Notes, patch)
- www.vulncheck.com/advisories/xenforo-stored-cross-site-scripting-via-bb-code-re… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-35054?
- CVE-2026-35054 is a medium-severity vulnerability in Xenforo, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2026-04-01.
- How severe is CVE-2026-35054?
- Medium severity. CVSS v3 base score is 6.4 out of 10.