CVE-2025-13048: StatCounter WordPress Plugin XSS Flaw

CVE-2025-13048 Overview

The StatCounter – Free Real Time Visitor Stats plugin for WordPress is vulnerable to Stored Cross-Site Scripting (XSS) via the user's Nickname field in all versions up to and including 2.1.0. This vulnerability stems from insufficient input sanitization and output escaping, allowing authenticated attackers with Contributor-level access or higher to inject arbitrary web scripts into pages. These malicious scripts execute whenever any user accesses the compromised page, potentially leading to session hijacking, credential theft, or further exploitation of site visitors.

Critical Impact

Authenticated attackers can inject persistent malicious scripts that execute in the context of any user viewing affected pages, potentially compromising administrator sessions and enabling full site takeover.

Affected Products

• StatCounter – Free Real Time Visitor Stats plugin for WordPress versions up to and including 2.1.0
• WordPress installations running the vulnerable StatCounter plugin versions

Discovery Timeline

• February 19, 2026 - CVE-2025-13048 published to NVD
• February 19, 2026 - Last updated in NVD database

Technical Details for CVE-2025-13048

Vulnerability Analysis

This Stored Cross-Site Scripting vulnerability exists in the StatCounter WordPress plugin's handling of the user Nickname field. The plugin fails to properly sanitize user-supplied input before storing it in the database and does not adequately escape the output when rendering the nickname on pages. This allows an attacker with at least Contributor-level permissions to craft a malicious nickname containing JavaScript code that persists in the database and executes in the browsers of other users viewing affected pages.

The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation). The attack can be launched remotely over the network and requires low privileges (Contributor access), making it accessible to a wider range of potential attackers. The scope is changed, meaning the vulnerability can impact resources beyond the vulnerable component itself—specifically, it can affect the browsers and sessions of other users viewing the page.

Root Cause

The root cause is the lack of proper input validation and output encoding in the StatCounter plugin's handling of user-provided Nickname data. When user input is stored without sanitization and later rendered in HTML output without proper escaping, it creates an opportunity for attackers to inject executable JavaScript code. The vulnerable code path at line 274 of StatCounter-Wordpress-Plugin.php fails to apply WordPress's built-in escaping functions such as esc_html() or wp_kses() before outputting user-controlled data.

Attack Vector

The attack vector involves an authenticated user with Contributor-level access or higher modifying their Nickname field to include malicious JavaScript payload. When this nickname is displayed on any page within the WordPress site, the unescaped script executes in the context of the viewing user's browser session. This allows the attacker to:

1. Steal session cookies and authentication tokens
2. Perform actions on behalf of authenticated users, including administrators
3. Redirect users to malicious external sites
4. Modify page content to display phishing forms or deceptive content
5. Escalate privileges if an administrator views the compromised page

The vulnerability requires no user interaction beyond viewing a page containing the malicious nickname, making it particularly dangerous in multi-author WordPress environments.

Detection Methods for CVE-2025-13048

Indicators of Compromise

• Unusual JavaScript code patterns within user nickname fields in the WordPress database
• Unexpected <script> tags or event handlers (e.g., onerror, onload) in stored user profile data
• Anomalous outbound network requests from client browsers to unknown external domains
• Reports of unexpected behavior or redirects when viewing pages with StatCounter integration

Detection Strategies

• Implement Content Security Policy (CSP) headers to detect and block inline script execution attempts
• Review WordPress database wp_users and related tables for suspicious JavaScript patterns in nickname fields
• Monitor server access logs for unusual patterns of profile update requests followed by page views
• Deploy web application firewall (WAF) rules to detect XSS payloads in form submissions

Monitoring Recommendations

• Enable WordPress audit logging to track all user profile modifications
• Configure real-time alerting for changes to user metadata fields containing script-like content
• Regularly scan stored content for XSS indicators using automated security tools
• Monitor browser console errors that may indicate blocked XSS attempts

How to Mitigate CVE-2025-13048

Immediate Actions Required

• Update the StatCounter – Free Real Time Visitor Stats plugin to version 2.1.1 or later immediately
• Review all existing user nicknames in the WordPress database for malicious content
• Temporarily restrict Contributor and Author role permissions until patching is complete
• Force logout all active sessions and require users to re-authenticate after patching

Patch Information

The vulnerability has been addressed in version 2.1.1 of the StatCounter plugin. The patch introduces proper input sanitization and output escaping for the user Nickname field, preventing the injection of executable scripts. For detailed technical information about the fix, refer to the WordPress Plugin Changeset Update and the patched plugin code. Additional details are available in the Wordfence Vulnerability Report.

Workarounds

• If immediate patching is not possible, temporarily deactivate the StatCounter plugin until an update can be applied
• Implement strict Content Security Policy headers that block inline script execution
• Use a WordPress security plugin to scan and sanitize stored user data for XSS patterns
• Restrict the ability to modify user nicknames to Administrators only through role capability management