Cross-Site Scripting Vulnerability in XenForo Web Forum Software
CVE-2026-35055

5.1MEDIUM

Key Information:

Vendor

Xen Projectforo

Status
Xen Projectforo
Vendor
CVE Published:
1 April 2026

What is CVE-2026-35055?

XenForo versions prior to 2.3.9 and 2.2.18 are susceptible to a cross-site scripting (XSS) vulnerability stemming from inadequate sanitization of user content in lightbox interactions. This allows attackers to inject malicious scripts that execute within the browser of users who engage with affected post content, potentially leading to unauthorized actions and data exposure.

Affected Version(s)

XenForo 2.3.0 < 2.3.9

XenForo 0 < 2.2.18

References

https://xenforo.com/community/threads/xenforo-2-3-9-inc-x...
vendor-advisorypatch
https://www.vulncheck.com/advisories/xenforo-cross-site-s...
third-party-advisory

CVSS V4

Score:
5.1
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

UwU
.