Membership Plugin - Restrict Content < 3.2.3 - Reflected XSS

Vulnerability

The Membership WordPress plugin before version 3.2.3 fails to sanitize and escape a parameter before outputting it back in the page. This leads to a Reflected Cross-Site Scripting (XSS) vulnerability. Affected versions are all prior to 3.2.3.

Exploitation

An attacker can craft a malicious URL containing the unsanitized parameter and trick a high-privilege user, such as an administrator, into clicking it. No authentication is required to deliver the payload, but user interaction (clicking the link) is needed.

Impact

Successful exploitation allows the attacker to inject arbitrary JavaScript into the target's browser session. This can lead to session hijacking, defacement, or actions performed on behalf of the victim. Because high-privilege users are targeted, the impact can be severe, potentially granting the attacker administrative control.

Mitigation

The vulnerability is fixed in version 3.2.3. Users should update the plugin to 3.2.3 or later, released on 2023-06-26 [1]. No other workarounds are documented for this specific issue.