CVE-2025-23675: MailChimp Import Plugin CSRF Vulnerability

CVE-2025-23675 Overview

CVE-2025-23675 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the Import Users to MailChimp WordPress plugin developed by Sana Ullah. This vulnerability allows attackers to chain CSRF with Stored Cross-Site Scripting (XSS), enabling malicious actors to inject persistent scripts into the affected WordPress site by tricking authenticated administrators into submitting crafted requests.

Critical Impact

Successful exploitation allows attackers to inject malicious scripts that persist in the WordPress database, potentially compromising all users who access the affected pages, leading to session hijacking, credential theft, and site defacement.

Affected Products

• Import Users to MailChimp WordPress Plugin version 1.0 and earlier
• WordPress installations running the vulnerable import-users-to-mailchimp plugin
• All websites using unpatched versions of this plugin

Discovery Timeline

• 2025-01-16 - CVE-2025-23675 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-23675

Vulnerability Analysis

This vulnerability combines two attack techniques: Cross-Site Request Forgery (CSRF) and Stored Cross-Site Scripting (XSS). The plugin fails to implement proper CSRF token validation on form submissions, allowing attackers to craft malicious requests that can be executed when an authenticated administrator visits an attacker-controlled page. Additionally, the plugin does not properly sanitize user input before storing it in the database, enabling the injection of malicious JavaScript that persists and executes whenever the stored data is rendered.

The chained nature of this vulnerability makes it particularly dangerous. An attacker first exploits the CSRF weakness to submit malicious data without proper authorization checks, and then the stored XSS component ensures the injected payload executes in the browsers of all users who view the affected content.

Root Cause

The root cause of CVE-2025-23675 stems from two critical security failures in the Import Users to MailChimp plugin:

1. Missing CSRF Protection: The plugin's form handling functions lack proper nonce verification, allowing cross-origin requests to be processed as legitimate administrative actions.

2. Insufficient Input Sanitization: User-supplied data is stored directly in the WordPress database without adequate sanitization or encoding, enabling script injection that persists across page loads.

These combined failures represent a violation of CWE-352 (Cross-Site Request Forgery) principles, where security-critical operations can be triggered by forged requests from external origins.

Attack Vector

The attack scenario for CVE-2025-23675 typically unfolds as follows:

1. The attacker crafts a malicious HTML page containing a hidden form that targets the vulnerable plugin endpoint
2. The form includes XSS payload data in fields that will be stored by the plugin
3. The attacker tricks an authenticated WordPress administrator into visiting the malicious page
4. The administrator's browser automatically submits the forged request with their valid session cookies
5. The plugin processes the request without validating the origin, storing the malicious script
6. When any user (including other administrators) views pages containing the stored data, the XSS payload executes

The vulnerability exploits the trust relationship between the user's browser and the WordPress installation. Since no code examples are available from verified sources, readers should refer to the Patchstack Vulnerability Report for detailed technical analysis.

Detection Methods for CVE-2025-23675

Indicators of Compromise

• Unexpected JavaScript code present in MailChimp import settings or related database tables
• Suspicious form submissions in WordPress access logs originating from external referrers
• User reports of browser redirects or unusual behavior when accessing plugin-related pages
• New or modified entries in wp_options or related tables containing encoded script tags

Detection Strategies

• Monitor WordPress admin action logs for plugin configuration changes made without corresponding admin page visits
• Implement Content Security Policy (CSP) headers to detect and block inline script execution
• Review database entries associated with the import-users-to-mailchimp plugin for HTML/JavaScript content
• Deploy Web Application Firewall (WAF) rules to detect XSS patterns in POST requests to plugin endpoints

Monitoring Recommendations

• Enable detailed logging for all WordPress administrative actions and plugin interactions
• Configure alerts for form submissions to plugin endpoints that lack valid WordPress nonces
• Implement regular automated scans of database content for embedded script tags
• Monitor outbound network connections for signs of data exfiltration resulting from XSS exploitation

How to Mitigate CVE-2025-23675

Immediate Actions Required

• Immediately disable or remove the Import Users to MailChimp plugin from affected WordPress installations
• Audit database tables associated with the plugin for any injected malicious content
• Review WordPress access logs for suspicious activity targeting the plugin's endpoints
• Scan affected sites with security plugins to detect any residual malicious scripts

Patch Information

Currently, no official patch information is available for this vulnerability. The affected versions include Import Users to MailChimp version 1.0 and all earlier versions. Website administrators should monitor the official WordPress plugin repository and the Patchstack Vulnerability Report for updates regarding security fixes.

Workarounds

• Disable the plugin entirely until a security patch is released
• Implement WAF rules to block requests to the plugin's vulnerable endpoints
• Apply custom code modifications to add nonce verification to the plugin's form handlers (advanced users only)
• Consider migrating to an alternative MailChimp integration plugin with active security maintenance

# Disable the vulnerable plugin via WP-CLI
wp plugin deactivate import-users-to-mailchimp

# Optionally remove the plugin entirely
wp plugin delete import-users-to-mailchimp

# Scan for malicious content in the database
wp db search "<script" --all-tables