CVE-2025-15476: Bucketlister Plugin Auth Bypass Flaw

CVE-2025-15476 Overview

The Bucketlister plugin for WordPress contains a broken access control vulnerability due to a missing capability check on the bucketlister_do_admin_ajax() function. This security flaw affects all versions up to and including 0.1.5, allowing authenticated attackers with Subscriber-level access or higher to perform unauthorized modifications to bucket list items.

Critical Impact

Authenticated users with minimal privileges (Subscriber level) can add, delete, or modify arbitrary bucket list items, potentially compromising data integrity across the WordPress installation.

Affected Products

• The Bucketlister WordPress Plugin version 0.1.5 and earlier
• WordPress installations with The Bucketlister plugin enabled
• All configurations allowing Subscriber-level user registration

Discovery Timeline

• 2026-02-07 - CVE CVE-2025-15476 published to NVD
• 2026-02-09 - Last updated in NVD database

Technical Details for CVE-2025-15476

Vulnerability Analysis

This vulnerability is classified under CWE-862 (Missing Authorization), which occurs when a software component does not perform an authorization check when an actor attempts to access a resource or perform an action. In the context of WordPress plugins, this typically manifests when AJAX handler functions fail to verify that the requesting user has appropriate capabilities before processing the request.

The vulnerable function bucketlister_do_admin_ajax() processes administrative actions without verifying whether the authenticated user has the necessary permissions to perform those operations. WordPress provides capability checking functions such as current_user_can() that should be used to verify user permissions before executing sensitive operations.

Root Cause

The root cause of this vulnerability is the absence of a proper capability check within the bucketlister_do_admin_ajax() function. WordPress plugins that handle administrative actions via AJAX must implement authorization checks to ensure that only users with appropriate roles (typically Administrator or Editor) can modify plugin data. The Bucketlister plugin fails to implement these checks, relying solely on authentication rather than proper authorization.

When an AJAX endpoint is registered in WordPress using wp_ajax_ hooks, any authenticated user can invoke that endpoint. Without explicit capability verification, the principle of least privilege is violated, and low-privileged users gain unauthorized access to administrative functionality.

Attack Vector

The attack vector is network-based and requires an authenticated user with at least Subscriber-level access to the WordPress installation. An attacker who has registered or compromised a Subscriber account can craft malicious AJAX requests to the vulnerable endpoint. These requests would be processed by the bucketlister_do_admin_ajax() function without proper authorization checks, allowing the attacker to:

1. Add arbitrary bucket list items that may contain misleading or malicious content
2. Delete existing bucket list items, causing data loss
3. Modify bucket list entries to alter their content or metadata

The attack requires no user interaction beyond the attacker being logged in with a valid Subscriber or higher account. For detailed technical analysis, refer to the WordPress Plugin Code Review and the Wordfence Vulnerability Report.

Detection Methods for CVE-2025-15476

Indicators of Compromise

• Unexpected modifications to bucket list items not corresponding to administrative activity
• Unusual AJAX requests to admin-ajax.php with action=bucketlister parameters from Subscriber-level accounts
• Database entries in the bucket list tables with creation or modification timestamps that don't align with legitimate administrative sessions
• Audit logs showing data modifications by users with Subscriber or Contributor roles

Detection Strategies

• Monitor WordPress AJAX request logs for calls to bucketlister_do_admin_ajax() from non-administrative users
• Implement WordPress activity logging plugins to track user actions and identify privilege abuse
• Review database audit trails for bucket list table modifications correlated with low-privileged user sessions
• Deploy web application firewall (WAF) rules to flag suspicious AJAX patterns targeting the vulnerable endpoint

Monitoring Recommendations

• Enable detailed logging for WordPress AJAX handlers to capture request parameters and user context
• Configure alerts for data modification events triggered by users with Subscriber or Contributor roles
• Implement database-level audit logging for tables used by The Bucketlister plugin
• Review access logs periodically for patterns indicative of authorization bypass attempts

How to Mitigate CVE-2025-15476

Immediate Actions Required

• Disable The Bucketlister plugin immediately until a patched version is available
• Review existing bucket list data for unauthorized modifications or deletions
• Audit user accounts with Subscriber-level access for any suspicious activity
• Consider restricting user registration or elevating the minimum capability required for registered users

Patch Information

As of the last update on 2026-02-09, users should monitor the official WordPress plugin repository and security advisories for a patched version of The Bucketlister plugin. The vulnerability affects version 0.1.5 and all prior versions. Check the Wordfence Vulnerability Report for updated remediation guidance.

Workarounds

• Deactivate and remove The Bucketlister plugin from WordPress installations until a secure version is released
• Implement a custom code snippet in your theme's functions.php to add capability checks to the vulnerable AJAX handler
• Use a security plugin with virtual patching capabilities to block exploitation attempts
• Restrict user registration or limit Subscriber-level accounts to trusted individuals only

# Deactivate the vulnerable plugin via WP-CLI
wp plugin deactivate the-bucketlister --path=/var/www/html/wordpress

# List all users with Subscriber role for audit
wp user list --role=subscriber --path=/var/www/html/wordpress

# Review recent plugin activity in WordPress database
wp db query "SELECT * FROM wp_options WHERE option_name LIKE '%bucketlister%'" --path=/var/www/html/wordpress