CVE-2025-15001: WordPress FS Registration Vulnerability

CVE-2025-15001 Overview

The FS Registration Password plugin for WordPress contains a critical privilege escalation vulnerability that allows unauthenticated attackers to take over arbitrary user accounts, including administrator accounts. This vulnerability exists in all versions up to and including 1.0.1 and stems from the plugin's failure to properly validate a user's identity before allowing password changes.

Critical Impact

Unauthenticated attackers can change any user's password, including administrator accounts, gaining full control of WordPress installations without any prior authentication.

Affected Products

• FS Registration Password plugin for WordPress versions up to and including 1.0.1
• WordPress installations using vulnerable versions of the plugin

Discovery Timeline

• 2026-01-06 - CVE-2025-15001 published to NVD
• 2026-01-08 - Last updated in NVD database

Technical Details for CVE-2025-15001

Vulnerability Analysis

This vulnerability is classified as CWE-639 (Authorization Bypass Through User-Controlled Key), which occurs when an application uses user-controlled input to determine which user's data to access or modify without proper authorization checks. In the context of the FS Registration Password plugin, the password reset functionality fails to adequately verify that the requesting user has the authority to change the target account's password.

The vulnerability enables a complete authentication bypass scenario where an attacker can modify any user's credentials without proving ownership of that account. Once an attacker changes an administrator's password, they gain full administrative access to the WordPress site, enabling content modification, user management, plugin installation, and potentially server-level access through malicious code injection.

Root Cause

The root cause lies in the plugin's Auth.php file, specifically in the password update functionality. The plugin accepts user-supplied identifiers (such as user IDs or email addresses) to determine which account's password should be changed, but fails to implement proper authorization checks to verify that the requester is the legitimate owner of that account. This allows any unauthenticated user to specify an arbitrary target account and set a new password.

Attack Vector

This vulnerability is exploitable over the network without any authentication or user interaction required. An attacker can craft malicious HTTP requests to the vulnerable password change endpoint, specifying an arbitrary target user (such as an administrator) and a new password of their choosing.

The attack flow typically involves:

1. Identifying a WordPress site using the vulnerable FS Registration Password plugin
2. Enumerating valid usernames or user IDs (often possible through WordPress's default user enumeration vectors)
3. Sending a crafted request to the password change endpoint with the target user's identifier
4. Logging in with the newly set password to gain access to the target account

Technical details of the vulnerable code can be found in the WordPress Plugin Source Code and the corresponding WordPress Plugin Changeset that addresses this issue.

Detection Methods for CVE-2025-15001

Indicators of Compromise

• Unexpected password reset activities in WordPress audit logs, particularly for administrator accounts
• Multiple failed login attempts followed by successful logins from new IP addresses
• Administrator account access from unfamiliar geographic locations or IP ranges
• Unexpected changes to site content, plugins, or user accounts
• Evidence of malicious HTTP requests targeting password change endpoints

Detection Strategies

• Monitor WordPress authentication logs for unauthorized password changes or suspicious reset attempts
• Implement web application firewall (WAF) rules to detect and block unusual patterns in password change requests
• Deploy SentinelOne Singularity to detect post-exploitation activities such as unauthorized plugin installations or file modifications
• Set up alerts for administrative account login events from new devices or locations

Monitoring Recommendations

• Enable comprehensive WordPress audit logging to capture all authentication and user modification events
• Configure real-time alerting for any password changes on privileged accounts
• Review server access logs regularly for anomalous request patterns to plugin endpoints
• Implement file integrity monitoring on WordPress core files and plugin directories

How to Mitigate CVE-2025-15001

Immediate Actions Required

• Update the FS Registration Password plugin to the latest patched version immediately
• Audit all user accounts, especially administrator accounts, for unauthorized password changes
• Force password resets for all administrative users if compromise is suspected
• Review WordPress audit logs for any suspicious activity during the exposure window
• Consider temporarily disabling the plugin if an update is not immediately available

Patch Information

The vulnerability has been addressed in a security update to the FS Registration Password plugin. Administrators should update to the latest available version through the WordPress plugin update mechanism. The security fix can be reviewed in the WordPress Plugin Changeset. Additional vulnerability details are available in the Wordfence Vulnerability Report.

Workarounds

• Deactivate and remove the FS Registration Password plugin until a patched version can be applied
• Implement additional authentication layers such as two-factor authentication for all administrative accounts
• Deploy a web application firewall with rules to filter suspicious password change requests
• Restrict access to WordPress admin areas by IP address where feasible

# WordPress CLI command to disable the vulnerable plugin
wp plugin deactivate registration-password

# Enable WordPress audit logging via wp-config.php
# Add the following line to wp-config.php:
# define('WP_DEBUG_LOG', true);