CVE-2025-13684: ARK Related Posts Plugin CSRF Vulnerability

CVE-2025-13684 Overview

CVE-2025-13684 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the ARK Related Posts plugin for WordPress through version 2.19. The flaw resides in the ark_rp_options_page function, which lacks proper nonce validation. Unauthenticated attackers can craft malicious requests that modify plugin configuration settings when a site administrator is tricked into clicking a link or visiting a controlled page. The issue is tracked under [CWE-352] and carries a medium severity rating. Exploitation requires user interaction from a privileged account, which limits the attack scope but does not eliminate the risk for sites with active administrators.

Critical Impact
Successful exploitation allows attackers to alter plugin configuration on behalf of an administrator, potentially degrading site behavior or enabling follow-on attacks.

Affected Products

ARK Related Posts plugin for WordPress version 2.19
Earlier versions of the ARK Related Posts plugin that share the vulnerable ark_rp_options_page implementation
WordPress sites installing the plugin from the WordPress.org plugin directory

Discovery Timeline

2025-12-05 - CVE-2025-13684 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-13684

Vulnerability Analysis

The ARK Related Posts plugin exposes an administrative settings page handled by the ark_rp_options_page function. This function processes configuration updates submitted through the WordPress admin interface but does not validate a WordPress nonce token before applying changes. WordPress nonces are the standard mechanism to bind state-changing requests to an authenticated session and protect against CSRF. Without this check, the plugin cannot distinguish between a legitimate administrator submission and a forged request originating from an attacker-controlled site.

The vulnerability is classified as Cross-Site Request Forgery under [CWE-352]. It requires the target administrator to be authenticated to WordPress and to interact with attacker-supplied content, such as a link in an email or a page embedding a hidden form. The attack does not permit direct code execution or data disclosure, but it does allow silent modification of plugin settings.

Root Cause

The root cause is missing or incorrect nonce validation on the ark_rp_options_page function in ark-relatedpost.php. The function should call check_admin_referer or wp_verify_nonce against a nonce generated with wp_nonce_field before persisting configuration changes. Because these checks are absent, any authenticated administrator session can be leveraged by an off-site attacker to submit form data.

Attack Vector

An attacker hosts a page containing an auto-submitting HTML form or JavaScript that targets the plugin's settings endpoint on the victim WordPress site. When an authenticated administrator visits the attacker's page, the browser sends the request with the administrator's session cookies attached. The plugin accepts the request and applies the attacker-supplied configuration values. Because there is no nonce, no origin check, and no additional confirmation, the modification succeeds silently.

For technical details of the affected code path, see the WordPress Plugin Source Code and the corrective WordPress Changeset #3416647.

Detection Methods for CVE-2025-13684

Indicators of Compromise

Unexpected changes to ARK Related Posts plugin configuration values without a corresponding administrator activity log entry
HTTP POST requests to the plugin's admin.php options handler with Referer headers pointing to external domains
Administrator sessions submitting settings changes shortly after visiting untrusted external links

Detection Strategies

Review web server access logs for POST requests to WordPress admin endpoints that carry external referrers or missing _wpnonce parameters
Deploy a WordPress activity log plugin to capture configuration changes and correlate them with administrator browsing patterns
Compare plugin settings against a known-good baseline using WordPress REST API or database snapshots

Monitoring Recommendations

Monitor administrator user agents and IPs for anomalous cross-origin submissions to plugin option pages
Alert on modifications to WordPress wp_options rows associated with the ARK Related Posts plugin outside scheduled maintenance windows
Track the Wordfence Vulnerability Report for updated exploitation signals

How to Mitigate CVE-2025-13684

Immediate Actions Required

Update the ARK Related Posts plugin to the version released in WordPress Changeset #3416647, which introduces nonce validation
Audit current plugin configuration values and reset any settings that appear inconsistent with administrative intent
Require administrators to log out of WordPress before browsing untrusted sites, or to use a dedicated browser profile for admin work

Patch Information

The vendor addressed the issue by adding nonce validation to the ark_rp_options_page handler. The fix is reflected in the plugin's trunk and tagged releases following WordPress Changeset #3416647. Site owners should upgrade past version 2.19 to obtain the patched code path.

Workarounds

Deactivate the ARK Related Posts plugin until the patched version is installed
Restrict access to /wp-admin/ by source IP using web server rules or a WordPress firewall
Enforce SameSite=Lax or SameSite=Strict cookies on the WordPress session to reduce cross-site request delivery

bash

# Example Nginx configuration to restrict wp-admin access by IP
location ^~ /wp-admin/ {
    allow 203.0.113.0/24;
    deny all;
    try_files $uri $uri/ /index.php?$args;
}