Description

Subscriber Privilege Escalation in WCFM Membership <= 2.11.11 versions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.1",
  "pubDate": "2026-09-03T17:17:26.117Z",
  "pubdate": "2026-09-03T17:17:26.117Z",
  "executiveSummary": "A privilege escalation vulnerability exists in the WCFM Membership plugin for WordPress in versions 2.11.11 and below. This security flaw stems from insufficient authorization checks during user profile updates or membership registration processes, allowing authenticated users with minimal privileges, such as Subscribers, to modify their account roles or gain unauthorized access to elevated administrative or vendor capabilities. The vulnerability poses a significant risk to the integrity and confidentiality of the WordPress installation, as it enables unauthorized vertical privilege escalation. By exploiting this flaw, a low-privileged attacker can bypass intended access controls to perform actions reserved for administrators or higher-tier roles. Exploitation requires the attacker to be authenticated as a registered user on the target site. The impact includes full site compromise, unauthorized access to sensitive vendor data, and the potential for persistent backdooring of the platform. Organizations utilizing affected versions of WCFM Membership are urged to prioritize updates to resolve this critical access control failure.",
  "technicalDetails": "The vulnerability resides within the WCFM Membership plugin's user management logic, specifically involving the handling of requests sent to the plugin's profile or membership update endpoints. The root cause is an insecure implementation of capability checks when processing incoming POST requests intended to modify user metadata or role assignments.\nThe attack flow commences when an authenticated user, assigned the Subscriber role, intercepts a request sent to the WCFM endpoint responsible for updating membership information or profile settings. By manipulating parameters within the request body, the attacker can inject key-value pairs that the plugin erroneously trusts and persists to the underlying WordPress 'wp_usermeta' or 'wp_users' database tables without sufficient server-side validation of the user's current permissions or the legitimacy of the requested role change.\nSpecifically, the plugin fails to enforce proper nonce validation or capability verification (e.g., current_user_can('manage_options')) before committing user role modifications or assigning specific membership plans that grant elevated access levels. Because the plugin processes these updates with the context of the current request without re-verifying authorization, an attacker can elevate their own account privileges to 'Administrator', 'Shop Manager', or 'Vendor' by simply appending the appropriate role identifier to the request payload.\nOnce the malicious payload is processed, the WordPress user object is updated, effectively granting the attacker the permissions associated with the escalated role. This post-exploitation impact allows the attacker to access backend administrative interfaces, manipulate store settings, modify configuration files, or inject malicious code into the site's environment. The vulnerability is characterized by a lack of strict input sanitization and an improper authorization bypass, where the plugin trusts user-supplied input to dictate role-based access control (RBAC) status. As this occurs within the application layer via legitimate protocol endpoints, it is difficult to detect using standard perimeter network security controls, necessitating a fix within the plugin code to enforce strict role-assignment restrictions."
}