Vulnerability · Published Apr 1, 2026 · Assigned by VulnCheck
CVE-2026-35055XenForo Cross-Site Scripting via Lightbox in Posts
Medium 6.1
In plain English
A medium-severity cross-site scripting in XenForo from XenForo. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities).
Severity (CVSS 3.1)6.1Medium
Exploit odds (30 days)0.2%top 94.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
XenForo before 2.3.9 and before 2.2.18 is vulnerable to cross-site scripting (XSS) related to lightbox usage in posts. An attacker can inject malicious scripts that execute when users interact with post content displayed in the lightbox.
Affected products (as reported)
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
References
- XenForo 2.3.9 (inc XFMG) & 2.2.18 Released (Security Fix) vendor-advisory, patch
- VulnCheck Advisory: XenForo Cross-Site Scripting via Lightbox in Posts third-party-advisory