CVE-2026-6203 PoC — User Registration & Membership <= 5.1.4 - Unauthenticated Open Redirect via 'redirect_to_on_logout' Parameter

Title:User Registration & Membership <= 5.1.4 - Unauthenticated Open Redirect via 'redirect_to_on_logout' Parameter (CVE-2026-6203)
Description:The User Registration & Membership plugin for WordPress is vulnerable to Open Redirect in versions up to and including 5.1.4. This is due to insufficient validation of user-supplied URLs passed via the 'redirect_to_on_logout' GET parameter before redirecting users. The `redirect_to_on_logout` GET parameter is passed directly to WordPress's `wp_redirect()` function instead of the domain-restricted `wp_safe_redirect()`. While `esc_url_raw()` is applied to sanitize malformed URLs, it does not restrict the redirect destination to the local domain, allowing an attacker to craft a specially formed link that redirects users to potentially malicious external URLs after logout, which could be used to facilitate phishing attacks.

User Registration & Membership WordPress plugin <= 5.1.4 contains an open redirect caused by insufficient validation of 'redirect_to_on_logout' parameter, letting attackers redirect users to malicious external URLs after logout, exploit requires crafted URL.

 id: CVE-2026-6203

info:
  name: User Registration & Membership WordPress plugin - Open Redirect
  a

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