CVE-2025-31455: Limit Max IPs Per User XSS Vulnerability

CVE-2025-31455 Overview

CVE-2025-31455 is a DOM-Based Cross-Site Scripting (XSS) vulnerability in the Limit Max IPs Per User WordPress plugin developed by ralxz. The flaw affects all plugin versions up to and including 1.5. The plugin fails to properly neutralize user-supplied input during web page generation, allowing attackers to inject malicious scripts that execute in the victim's browser. Successful exploitation requires user interaction, such as clicking a crafted link. The issue is tracked under CWE-79 and documented in the Patchstack WordPress Vulnerability Report.

Critical Impact

Attackers can execute arbitrary JavaScript in the browser context of WordPress users, enabling session hijacking, credential theft, and unauthorized actions against the WordPress site.

Affected Products

• ralxz Limit Max IPs Per User WordPress plugin
• All versions from n/a through 1.5
• WordPress sites running the vulnerable plugin

Discovery Timeline

• 2025-04-01 - CVE-2025-31455 published to NVD
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-31455

Vulnerability Analysis

The Limit Max IPs Per User plugin processes attacker-controllable input and writes it into the Document Object Model (DOM) without proper sanitization or output encoding. This produces a DOM-Based XSS condition classified under [CWE-79]. Because the vulnerable sink resides in client-side JavaScript, the malicious payload never needs to reach the server in its raw form. The attack scope is changed, meaning injected scripts can affect resources beyond the originally vulnerable component.

Root Cause

The root cause is improper neutralization of input during web page generation. The plugin reads data from a source controlled by the attacker, such as URL fragments or query parameters, and writes that data into the page using an unsafe sink. The absence of contextual output encoding or sanitization permits HTML and JavaScript constructs to be rendered as executable code rather than inert text.

Attack Vector

An attacker crafts a URL containing a malicious payload targeting the vulnerable plugin endpoint. The attacker then delivers the URL via phishing, forum posts, or social engineering. When an authenticated WordPress user clicks the link, the embedded JavaScript executes in the user's browser under the site's origin. The attacker can then steal session cookies, perform actions as the victim, or pivot to administrator accounts when a privileged user is targeted. Refer to the Patchstack advisory for additional technical context.

Detection Methods for CVE-2025-31455

Indicators of Compromise

• HTTP requests to WordPress URLs containing encoded <script>, javascript:, or onerror= payloads referencing plugin parameters
• Unexpected outbound requests from authenticated user browsers to attacker-controlled domains
• Anomalous administrator account activity following user clicks on external links
• Web server access logs showing referrer chains from untrusted external sources to plugin endpoints

Detection Strategies

• Inspect WordPress access logs for query strings and URL fragments containing HTML or JavaScript syntax targeting the limit-max-ips-per-user plugin path
• Deploy a Web Application Firewall (WAF) with rules tuned to identify reflected and DOM-based XSS payload patterns
• Implement Content Security Policy (CSP) reporting to capture script execution violations originating from plugin pages

Monitoring Recommendations

• Monitor authenticated WordPress sessions for unusual administrative actions performed shortly after navigation events
• Audit installed plugin versions across WordPress deployments to identify instances running Limit Max IPs Per User 1.5 or earlier
• Track browser-side telemetry, including CSP violation reports, for indicators of unexpected script execution

How to Mitigate CVE-2025-31455

Immediate Actions Required

• Identify all WordPress installations running the Limit Max IPs Per User plugin and inventory their versions
• Deactivate and remove the plugin if a patched release is not yet available from the vendor
• Invalidate existing administrator sessions and rotate credentials if exploitation is suspected
• Enforce a strict Content Security Policy on WordPress sites to limit the impact of script injection

Patch Information

At the time of publication, no fixed version has been listed in the available references. Administrators should monitor the Patchstack advisory and the WordPress plugin repository for an updated release addressing CVE-2025-31455.

Workarounds

• Remove the vulnerable plugin until a patched version is released
• Deploy WAF rules that block requests containing XSS payload patterns directed at plugin parameters
• Apply a restrictive Content Security Policy that disallows inline scripts and untrusted script sources
• Train administrators and editors to avoid clicking unsolicited links targeting their WordPress site

# Example restrictive CSP header for WordPress (adjust for your environment)
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'; report-uri /csp-report"