CVE-2025-28867: Frontpage Category Filter CSRF Flaw

CVE-2025-28867 Overview

A Cross-Site Request Forgery (CSRF) vulnerability has been identified in the Frontpage Category Filter WordPress plugin developed by stesvis. This vulnerability allows attackers to trick authenticated users into executing unintended actions on the WordPress site by crafting malicious requests. When a logged-in administrator visits a malicious page or clicks a crafted link, the attacker can perform unauthorized actions with the victim's privileges.

Critical Impact

Attackers can leverage this CSRF vulnerability to perform unauthorized administrative actions, potentially modifying plugin settings, altering category filters on the frontpage, or executing other privileged operations without user consent.

Affected Products

• stesvis Frontpage Category Filter versions through 1.0.2
• WordPress installations using the vulnerable plugin
• All configurations of the frontpage-category-filter plugin

Discovery Timeline

• 2025-03-11 - CVE CVE-2025-28867 published to NVD
• 2026-04-01 - Last updated in NVD database

Technical Details for CVE-2025-28867

Vulnerability Analysis

This CSRF vulnerability exists because the Frontpage Category Filter plugin fails to implement proper anti-CSRF token validation for state-changing operations. The plugin does not verify that incoming requests originate from legitimate user actions within the WordPress admin interface. This allows an attacker to craft malicious HTML pages containing hidden forms or JavaScript that automatically submit requests to the vulnerable plugin endpoints when visited by an authenticated WordPress administrator.

The vulnerability affects the plugin's core functionality related to managing category filters displayed on the WordPress frontpage. Without proper nonce verification, any administrative action exposed by the plugin becomes susceptible to cross-site request forgery attacks.

Root Cause

The root cause of CVE-2025-28867 is the absence of WordPress nonce verification in the plugin's form handlers and AJAX endpoints. WordPress provides built-in CSRF protection through its nonce system (wp_nonce_field() and wp_verify_nonce()), but the Frontpage Category Filter plugin versions through 1.0.2 do not implement these security mechanisms for critical operations. This allows cross-origin requests to be processed as if they were legitimate user actions.

Attack Vector

The attack requires social engineering to lure an authenticated WordPress administrator to a malicious website or page containing the CSRF payload. The attacker hosts a page with a hidden form that targets the vulnerable plugin endpoints. When the victim loads the page, the form automatically submits using JavaScript, causing the victim's browser to send an authenticated request to their WordPress site. Since the plugin lacks CSRF protection, the malicious request is processed with the administrator's session credentials.

The attack can be delivered through various vectors including phishing emails with links, malicious advertisements, compromised websites, or forum posts containing embedded content targeting WordPress administrators.

Detection Methods for CVE-2025-28867

Indicators of Compromise

• Unexpected changes to frontpage category filter settings without administrator action
• Web server access logs showing POST requests to plugin endpoints from external referrers
• WordPress admin activity logs indicating configuration changes at unusual times
• HTTP requests to plugin-related URLs with suspicious Referer headers from external domains

Detection Strategies

• Monitor WordPress admin activity logs for unauthorized configuration changes to the Frontpage Category Filter plugin
• Implement web application firewall (WAF) rules to detect and block requests with suspicious cross-origin referrers targeting WordPress admin endpoints
• Review web server access logs for POST requests to /wp-admin/ paths originating from external domains
• Deploy security plugins that track and alert on administrative action anomalies

Monitoring Recommendations

• Enable comprehensive WordPress admin activity logging to capture all plugin configuration changes
• Configure alerts for administrative actions occurring outside normal business hours
• Monitor for rapid sequential requests to plugin endpoints that may indicate automated CSRF exploitation
• Implement Content Security Policy (CSP) headers to help mitigate cross-origin attack vectors

How to Mitigate CVE-2025-28867

Immediate Actions Required

• Deactivate and remove the Frontpage Category Filter plugin (frontpage-category-filter) until a patched version is available
• Review WordPress admin activity logs for any suspicious configuration changes
• Verify that frontpage category settings have not been tampered with
• Educate WordPress administrators about the risks of clicking unknown links while logged into the admin panel

Patch Information

As of the last update, no official patch has been released for this vulnerability. The affected versions include all releases through 1.0.2. Organizations should monitor the Patchstack WordPress Plugin Vulnerability Database for updates and patch availability. Consider replacing the plugin with an alternative that implements proper CSRF protections.

Workarounds

• Remove or deactivate the Frontpage Category Filter plugin until a security update is available
• Implement a Web Application Firewall (WAF) with rules to validate request origins and block suspicious cross-site requests
• Use browser extensions or policies that restrict automatic form submissions from external sites
• Require re-authentication for sensitive administrative actions when possible
• Log out of WordPress admin sessions when browsing other websites

# WordPress CLI command to deactivate the vulnerable plugin
wp plugin deactivate frontpage-category-filter

# Verify plugin has been deactivated
wp plugin list --status=inactive | grep frontpage-category-filter

# Optional: Remove the plugin entirely
wp plugin delete frontpage-category-filter