CVE-2025-46512: Custom Functions Plugin CSRF Vulnerability

CVE-2025-46512 Overview

CVE-2025-46512 is a Cross-Site Request Forgery (CSRF) vulnerability in the WordPress Custom Functions Plugin developed by Shamim Hasan. This vulnerability allows attackers to chain CSRF with Stored Cross-Site Scripting (XSS), enabling malicious actors to inject persistent scripts into the affected WordPress installation by tricking authenticated administrators into performing unintended actions.

Critical Impact

Attackers can exploit this CSRF vulnerability to inject stored XSS payloads, potentially compromising administrator sessions, stealing credentials, or performing unauthorized actions on behalf of authenticated users.

Affected Products

• WordPress Custom Functions Plugin version 1.1 and earlier
• All installations using Custom Functions Plugin through version 1.1

Discovery Timeline

• 2025-04-24 - CVE-2025-46512 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-46512

Vulnerability Analysis

This vulnerability represents a chained attack combining Cross-Site Request Forgery (CSRF) with Stored Cross-Site Scripting (XSS). The Custom Functions Plugin fails to implement proper CSRF token validation on critical form submissions, allowing attackers to craft malicious requests that execute in the context of an authenticated administrator's session. When combined with the absence of output sanitization, this enables the injection of persistent JavaScript code that executes whenever the affected page is rendered.

The attack chain requires social engineering to trick an authenticated administrator into visiting a malicious page or clicking a crafted link while logged into their WordPress dashboard. Once the CSRF attack succeeds, the XSS payload is stored in the database and persists across sessions.

Root Cause

The root cause of this vulnerability is the absence of proper CSRF protection mechanisms (such as nonce verification) in the Custom Functions Plugin's form handling, combined with insufficient input sanitization and output encoding. WordPress provides built-in functions like wp_nonce_field() and wp_verify_nonce() for CSRF protection, as well as esc_html() and wp_kses() for output sanitization, but these were not properly implemented in the affected versions.

Attack Vector

The attack vector involves crafting a malicious HTML page or link that submits a forged request to the Custom Functions Plugin endpoint. When an authenticated WordPress administrator visits the attacker-controlled page, their browser automatically includes their session cookies with the malicious request, causing the server to process the request as if it were legitimate.

The attack flow typically involves:

1. An attacker creates a malicious webpage containing a hidden form that targets the vulnerable Custom Functions Plugin endpoint
2. The form includes XSS payloads in the request parameters
3. When an administrator visits the malicious page, the form auto-submits using JavaScript
4. The WordPress site processes the request, storing the malicious script
5. Subsequent visitors to the affected WordPress page have the XSS payload execute in their browsers

For technical details on exploiting this vulnerability, refer to the Patchstack Security Vulnerability Report.

Detection Methods for CVE-2025-46512

Indicators of Compromise

• Unexpected modifications to custom function configurations in the WordPress database
• Suspicious JavaScript code appearing in plugin settings or content areas
• Browser console errors or unexpected script execution on WordPress admin pages
• Unusual outbound network connections from client browsers when accessing the WordPress site

Detection Strategies

• Review HTTP access logs for suspicious POST requests to Custom Functions Plugin endpoints from external referrers
• Monitor WordPress database tables associated with the Custom Functions Plugin for unauthorized modifications
• Implement Content Security Policy (CSP) headers to detect and block inline script execution attempts
• Use WordPress security plugins that monitor for configuration changes and alert on suspicious activity

Monitoring Recommendations

• Enable detailed logging for all WordPress plugin configuration changes
• Configure web application firewall (WAF) rules to detect CSRF attack patterns and XSS payloads
• Implement browser-side monitoring through CSP violation reporting
• Regularly audit stored content in the Custom Functions Plugin for unauthorized scripts

How to Mitigate CVE-2025-46512

Immediate Actions Required

• Disable or deactivate the Custom Functions Plugin until a patched version is available
• Review and remove any suspicious code or scripts that may have been injected through this vulnerability
• Audit WordPress administrator accounts for signs of compromise
• Implement additional CSRF protection at the web application firewall level

Patch Information

Users should check for an updated version of the Custom Functions Plugin that addresses this CSRF to Stored XSS vulnerability. Monitor the Patchstack Security Advisory for updates on patch availability. Consider removing the plugin entirely if a patch is not released in a timely manner.

Workarounds

• Disable the Custom Functions Plugin until a security patch is released
• Implement strict Content Security Policy headers to mitigate the impact of stored XSS
• Use a Web Application Firewall (WAF) with rules to block CSRF attacks and XSS payloads
• Limit administrator access to trusted IP addresses to reduce the attack surface
• Train administrators to avoid clicking links from untrusted sources while logged into WordPress

# Example Content Security Policy header configuration for Apache
# Add to .htaccess file to help mitigate XSS impact
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'"