CVE-2026-12426 in Members Plugin
Summary
by MITRE • 07/11/2026
The Members – Membership & User Role Editor Plugin plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 3.2.22 via the members_filter_protected_posts_for_rest. This makes it possible for unauthenticated attackers to extract determine the existence and exact count of access-restricted posts, and use per-page pagination as a boolean oracle to infer keywords and content contained within those hidden restricted posts.
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Analysis
by VulDB Data Team • 07/11/2026
The vulnerability in the Members – Membership & User Role Editor Plugin for WordPress represents a critical sensitive information exposure flaw that affects all versions up to and including 3.2.22. This issue stems from improper access control implementation within the plugin's REST API endpoints, specifically through the members_filter_protected_posts_for_rest functionality. The vulnerability allows unauthenticated attackers to gain unauthorized knowledge about protected content by leveraging the plugin's handling of restricted posts through the WordPress REST API. Attackers can determine both the existence and precise count of access-restricted posts, creating a significant information disclosure risk that extends beyond simple content enumeration.
The technical exploitation of this vulnerability occurs through a sophisticated boolean oracle attack pattern where attackers utilize per-page pagination parameters to infer information about hidden content. By manipulating pagination offsets and analyzing response sizes or counts, adversaries can systematically determine the presence of specific keywords within protected posts without having legitimate access credentials. This methodical approach transforms what should be secure access controls into a reconnaissance tool for content discovery, effectively bypassing WordPress's built-in permission systems and user role management mechanisms.
The operational impact of this vulnerability extends far beyond simple information disclosure, creating potential downstream risks for organizations relying on the plugin for membership management and content protection. Attackers can use the discovered information to plan more targeted attacks, such as social engineering campaigns based on inferred content, or to identify valuable assets within the protected content repository. The vulnerability particularly affects sites where sensitive information is stored in protected posts, including private documents, member-only resources, or confidential communications that should remain inaccessible to unauthorized users.
This vulnerability maps directly to CWE-200 (Information Exposure) and CWE-352 (Cross-Site Request Forgery) categories within the Common Weakness Enumeration framework, representing a clear failure in proper access control enforcement. The ATT&CK framework categorizes this as a reconnaissance technique under T1594 (Compromise Infrastructure) and T1589 (Gather Victim Identity Information), as attackers can systematically discover valuable information about protected content. Additionally, the vulnerability demonstrates poor input validation and insufficient authentication checks in API endpoint implementations, which aligns with ATT&CK tactic T1078 (Valid Accounts) when considering the potential for credential harvesting or account compromise through information gathering.
Mitigation strategies should include immediate plugin updates to versions that address this vulnerability, implementation of additional access control measures through .htaccess rules or custom firewall configurations, and comprehensive monitoring of REST API endpoints for unusual query patterns. Organizations should also consider implementing rate limiting on API requests and conducting regular security audits of WordPress plugins to identify similar access control flaws. The most effective long-term solution involves ensuring all plugin developers implement proper authentication checks and access controls at the API endpoint level, preventing unauthorized users from gaining any information about restricted content through pagination-based reconnaissance techniques.