CVE-2026-14855

Overview

The RT Mega Menu plugin for WordPress up to version 1.5.1 suffers from a Stored Cross-Site Scripting vulnerability via the 'css[left]' parameter. This flaw arises from insufficient input sanitization and output escaping. It matters because authenticated users with subscriber-level access can inject arbitrary web scripts that execute in the context of other users visiting the affected pages.

Description

The RT Mega Menu plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'css[left]' parameter in all versions up to, and including, 1.5.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Impact

The vulnerability primarily impacts Integrity and Confidentiality by potentially allowing unauthorized script execution within a victim's browser session. Authenticated attackers with low-privilege (Subscriber) access can leverage this flaw to target other users, including administrators, who view the injected pages. Successful exploitation could lead to session hijacking, defacement, or unintended administrative actions performed on behalf of the victim.

Remediation

Update the RT Mega Menu plugin to a version later than 1.5.1 as soon as a patched release is made available by the vendor. Restrict low-privileged user roles from accessing or configuring plugin settings if feasible. Implement robust Web Application Firewall (WAF) rules to detect and block suspicious script injections targeting plugin parameters.

Risk context

This vulnerability is rated as medium severity with a CVSS v3 score of 6.4, indicating moderate risk. While it requires authenticated access, the low barrier of subscriber-level privileges increases exposure on sites that allow open registration.

Affected products

• RT Mega Menu plugin for WordPress