CVE-2026-35055: XenForo Cross-Site Scripting via Lightbox in Posts

Published Apr 1, 2026
·
Updated

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 Software

3 affected components
XenForo Xenforo<2.3.9, <2.2.18
XenForo Xenforo<2.2.18
XenForo Xenforo>=2.3.0<2.3.9

Event History

Apr 1, 2026
CVE Published
via MITRE·12:30 AM
Data Sourced
via MITRE·12:30 AM
DescriptionSeverityWeakness
Data Sourced
via NVD·01:16 AM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2026-35055?

CVE-2026-35055 is a critical vulnerability that involves cross-site scripting (XSS) due to improper handling of lightbox usage in XenForo.

2

How do I fix CVE-2026-35055?

To fix CVE-2026-35055, upgrade XenForo to version 2.3.9 or 2.2.18 or later.

3

What versions of XenForo are affected by CVE-2026-35055?

CVE-2026-35055 affects XenForo versions prior to 2.3.9 and 2.2.18.

4

What can an attacker do with CVE-2026-35055?

An attacker can exploit CVE-2026-35055 to inject malicious scripts that execute in the user's browser when they interact with post content in the lightbox.

5

What are the consequences of exploitation of CVE-2026-35055?

Exploitation of CVE-2026-35055 can lead to unauthorized access to sensitive user data, session hijacking, or redirecting users to malicious sites.

Contact

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