CVE-2025-25139: WP Custom Post RSS Feed CSRF Vulnerability

CVE-2025-25139 Overview

CVE-2025-25139 is a Cross-Site Request Forgery (CSRF) vulnerability in the WP Custom Post RSS Feed WordPress plugin developed by Cynob IT Consultancy. This vulnerability allows attackers to chain CSRF with Stored Cross-Site Scripting (XSS), enabling malicious actors to inject persistent scripts into WordPress sites by tricking authenticated administrators into performing unintended actions.

Critical Impact

Attackers can exploit this CSRF vulnerability to inject malicious JavaScript that persists in the WordPress database, potentially compromising all visitors to the affected site and enabling session hijacking, credential theft, or further malware distribution.

Affected Products

• WP Custom Post RSS Feed plugin version 1.0.0 and earlier
• WordPress sites using the wp-custom-post-rss-feed plugin
• All installations of the affected plugin without security patches

Discovery Timeline

• 2025-02-07 - CVE-2025-25139 published to NVD
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-25139

Vulnerability Analysis

This vulnerability combines two web application security weaknesses: Cross-Site Request Forgery (CSRF) and Stored Cross-Site Scripting (XSS). The WP Custom Post RSS Feed plugin fails to implement proper CSRF token validation on form submissions, allowing attackers to craft malicious requests that execute in the context of an authenticated administrator's session.

When an administrator visits a malicious page while logged into their WordPress site, the attacker-controlled page can submit forms to the vulnerable plugin endpoints. Because the plugin also lacks proper output encoding and input sanitization, the attacker can inject JavaScript code that gets stored in the WordPress database and subsequently executes for all users viewing the affected content.

The network-based attack vector with low complexity makes this vulnerability particularly concerning for WordPress site administrators. User interaction is required (the victim must visit a malicious page), but no prior authentication is needed for the attacker to craft and deploy the exploit.

Root Cause

The root cause of this vulnerability is the absence of CSRF protection mechanisms (such as nonce verification) in the plugin's form handling functions, combined with insufficient input sanitization and output encoding when processing user-supplied data. WordPress provides built-in functions like wp_nonce_field() and wp_verify_nonce() for CSRF protection, and esc_html() and wp_kses() for XSS prevention, but the plugin fails to properly implement these security measures.

Attack Vector

The attack scenario involves an adversary creating a malicious webpage containing a hidden form that targets the vulnerable plugin's settings or content submission endpoints. The form is pre-populated with XSS payload (malicious JavaScript). When a logged-in WordPress administrator visits this malicious page, the form auto-submits via JavaScript, sending the malicious payload to the WordPress site.

Due to the missing CSRF validation, the WordPress installation accepts the request as legitimate, and the XSS payload is stored in the database. From that point forward, any user viewing the affected RSS feed content or plugin settings page will have the malicious JavaScript execute in their browser, potentially leading to session hijacking, administrative account takeover, or drive-by malware downloads.

The vulnerability is particularly dangerous because the injected scripts persist across user sessions and can affect multiple visitors, including other administrators.

Detection Methods for CVE-2025-25139

Indicators of Compromise

• Unexpected JavaScript code or <script> tags in RSS feed content or plugin settings
• Unusual HTTP POST requests to plugin endpoints from external referrers
• Browser console errors or unexpected script execution on pages served by the plugin
• Modified plugin settings that administrators did not change

Detection Strategies

• Monitor WordPress audit logs for unauthorized changes to the WP Custom Post RSS Feed plugin settings
• Implement Web Application Firewall (WAF) rules to detect CSRF attacks and XSS payloads targeting plugin endpoints
• Review database content associated with the plugin for malicious script injections
• Deploy browser-based security extensions that alert on unexpected cross-origin form submissions

Monitoring Recommendations

• Enable comprehensive logging for all administrative actions in WordPress
• Configure alerts for modifications to plugin settings from unusual IP addresses or referrer headers
• Implement Content Security Policy (CSP) headers to mitigate the impact of successful XSS injection
• Regularly audit plugin-stored data for suspicious content patterns

How to Mitigate CVE-2025-25139

Immediate Actions Required

• Deactivate and remove the WP Custom Post RSS Feed plugin (wp-custom-post-rss-feed) until a patched version is available
• Review WordPress database and plugin settings for any injected malicious scripts
• Audit administrator sessions and consider invalidating all active sessions as a precaution
• Implement a Web Application Firewall (WAF) with CSRF and XSS protection rules

Patch Information

As of the last available data, all versions of the WP Custom Post RSS Feed plugin through version 1.0.0 are affected. Site administrators should monitor the Patchstack Vulnerability Advisory for updates on a security patch from Cynob IT Consultancy. Until a fix is released, removing the plugin is the recommended approach.

Workarounds

• Disable the plugin entirely until a security patch is released
• Restrict administrator access to the WordPress dashboard from trusted IP addresses only
• Implement additional authentication factors for WordPress administrative actions
• Use security plugins that add CSRF protection at the application layer for vulnerable endpoints

# Disable the vulnerable plugin via WP-CLI
wp plugin deactivate wp-custom-post-rss-feed

# Verify the plugin is deactivated
wp plugin status wp-custom-post-rss-feed

# Optional: Remove the plugin completely
wp plugin delete wp-custom-post-rss-feed