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.

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)

EPSS: 0.000 (10.3th percentile) — read the EPSS interpretation.

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.

Affected products

Xenforo — versions 2.3.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

XenForo 2.3.9 (inc XFMG) & 2.2.18 Released (Security Fix) (vendor-advisory, patch)
VulnCheck Advisory: XenForo Stored Cross-Site Scripting via BB Code Rendering (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.