CVE-2025-23881: LJ Custom Menu Links XSS Vulnerability

CVE-2025-23881 Overview

CVE-2025-23881 is a reflected Cross-Site Scripting (XSS) vulnerability in the LJ Custom Menu Links WordPress plugin by littlejon. The plugin fails to neutralize user-supplied input during web page generation, classified as [CWE-79]. All versions up to and including 2.5 are affected. Attackers can craft malicious links that, when clicked by an authenticated or unauthenticated user, execute arbitrary JavaScript in the victim's browser session. The vulnerability requires user interaction and changes security scope, allowing access to resources beyond the vulnerable component.

Critical Impact
Successful exploitation enables session hijacking, credential theft, and unauthorized actions performed in the context of the victim's browser session on the WordPress site.

Affected Products

LJ Custom Menu Links plugin for WordPress, versions up to and including 2.5
WordPress installations with the lj-custom-menu-links plugin enabled
Vendor: littlejon

Discovery Timeline

2025-03-03 - CVE-2025-23881 published to NVD
2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-23881

Vulnerability Analysis

The LJ Custom Menu Links plugin processes user-controlled input and reflects it back into HTML responses without proper output encoding or input sanitization. This pattern enables reflected XSS attacks where malicious payloads delivered via crafted URLs execute in the victim's browser context. The flaw falls under [CWE-79] Improper Neutralization of Input During Web Page Generation. Because the vulnerability operates with a changed security scope, payloads executing in the browser can interact with resources outside the originating plugin's authority, including the broader WordPress administrative interface.

Root Cause

The plugin's request handlers accept query parameters or form fields and embed them directly into rendered HTML without applying WordPress sanitization functions such as esc_html(), esc_attr(), or wp_kses(). The absence of contextual output encoding allows attacker-supplied markup and script tags to be interpreted by the browser as executable code rather than data.

Attack Vector

An attacker constructs a URL containing a JavaScript payload in a vulnerable parameter handled by the plugin. The attacker delivers this link through phishing emails, social media, or malicious referrers. When a logged-in WordPress user clicks the link, the injected script executes in their authenticated session, enabling theft of session cookies, exfiltration of nonces, forced administrative actions, or redirection to attacker-controlled infrastructure.

The vulnerability requires user interaction. Technical exploitation details are available in the Patchstack WordPress Vulnerability Advisory.

Detection Methods for CVE-2025-23881

Indicators of Compromise

HTTP request logs containing URL parameters with <script>, javascript:, onerror=, or onload= patterns directed at lj-custom-menu-links endpoints
Outbound network connections from administrator browsers to unrecognized domains shortly after clicking inbound links
Unexpected WordPress administrative actions such as user creation, plugin installation, or theme modification correlated with administrator sessions

Detection Strategies

Inspect web server access logs for encoded XSS payloads targeting plugin parameters, including URL-encoded %3Cscript%3E and HTML entity variants
Deploy a Web Application Firewall (WAF) rule set that flags reflected XSS signatures against the WordPress request path
Correlate referrer headers with administrative session activity to identify links arriving from external sources

Monitoring Recommendations

Enable verbose WordPress audit logging for administrative actions and authentication events
Monitor browser security headers such as Content-Security-Policy violation reports for blocked inline script execution
Alert on anomalous outbound DNS or HTTP traffic originating from administrator workstations during WordPress sessions

How to Mitigate CVE-2025-23881

Immediate Actions Required

Deactivate the LJ Custom Menu Links plugin until a patched version is verified and deployed
Force re-authentication for all WordPress administrators and rotate any session cookies or API keys that may have been exposed
Review WordPress user accounts, plugins, and themes for unauthorized additions or modifications

Patch Information

No fixed version is identified in the published advisory at the time of NVD publication. The advisory lists versions through 2.5 as affected. Monitor the Patchstack vulnerability entry and the WordPress plugin repository for updated releases.

Workarounds

Replace the plugin with an actively maintained alternative that provides equivalent custom menu link functionality
Deploy a WAF policy that filters reflected XSS payloads in query strings targeting WordPress endpoints
Enforce a strict Content-Security-Policy header that disallows inline script execution and restricts script sources to trusted origins
Train administrators to avoid clicking unsolicited links pointing to the WordPress admin interface

bash

# Example: disable the vulnerable plugin via WP-CLI
wp plugin deactivate lj-custom-menu-links
wp plugin delete lj-custom-menu-links