VulnerabilityAnalyzed

CVE-2026-35055

XenForo before 2.3.9 and before 2.2.18 is vulnerable to cross-site scripting (XSS) related to lightbox usage in posts.

MEDIUM 5.1EPSS 0.15%

Does this matter?

Lower severity and a low EPSS score (0.15%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 4.0: 5.1 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.15% probability · 5th percentile
CISA KEV: Not listed
Weakness: CWE-79
Affected: xenforo/xenforo
Source: disclosure@vulncheck.com

References

https://www.vulncheck.com/advisories/xenforo-cross-site-scripting-via-lightbox-in-postsThird Party Advisory
https://xenforo.com/community/threads/xenforo-2-3-9-inc-xfmg-2-2-18-released-security-fix.235659/Release Notes

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.