WP-Members Membership Plugin Stored Cross-Site Scripting Vulnerability

A stored cross-site scripting vulnerability has been identified in the WP-Members Membership Plugin for WordPress, affecting all versions through 3.5.4.1. The issue arises from inadequate input sanitization and output escaping of user-supplied attributes in the 'wpmem_login_link' shortcode. This vulnerability allows authenticated attackers with contributor-level access or higher to inject arbitrary scripts into pages, which are executed when users access the affected pages.

Impact

Exploitation of this vulnerability allows for stored cross-site scripting, where injected scripts are executed in the context of the user viewing the page.

Reproduction

To reproduce this vulnerability, an authenticated user with contributor-level access or higher can use the 'wpmem_login_link' shortcode. The injected script will be executed when the page is accessed by another user.

Remediation

Users are advised to update the WP-Members Membership Plugin to version 3.5.4.2 or later.