What the vulnerability does
01Description
The Ultimate Member – User Profile, Registration, Login, Member Directory, Content Restriction & Membership Plugin plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 2.11.0 via the ajax_get_members function. This is due to the use of a predictable low-entropy token (5 hex characters derived from md5 of post ID) to identify member directories and insufficient authorization checks on the unauthenticated AJAX endpoint. This makes it possible for unauthenticated attackers to extract sensitive data including usernames, display names, user roles (including administrator accounts), profile URLs, and user IDs by enumerating predictable directory_id values or brute-forcing the small 16^5 token space.
Explanation of Vulnerability in Simple Terms
02Summary
Ultimate Member versions up to 2.11.0 expose sensitive information that can be accessed over the network without authentication. An attacker can retrieve this data directly without needing to log in or interact with a user. The vulnerability affects the plugin's core functionality and may expose user profile data or other protected information.
What an attacker can do
03Attacker Capabilities
Read sensitive information from the site without logging in.
Potential impact on your site
04Site Impact
User data or other sensitive information may be visible to unauthenticated visitors.
Conditions required to exploit
05Prerequisites
Network access to the site; no authentication or user interaction required.
Key dates
06Disclosure timeline
December 20, 2025
CVE published
April 8, 2026
Record updated
