The Page and Post Restriction plugin for WordPress is vulnerable to Authentication Bypass in all…

Why it is Yellow

• CVSS 6.5 medium

References

• https://plugins.trac.wordpress.org/browser/page-and-post-restriction/tags/1.6.0/page-and-post-restriction.php#L54
• https://plugins.trac.wordpress.org/browser/page-and-post-restriction/tags/1.6.0/page-and-post-restriction.php#L78
• https://plugins.trac.wordpress.org/browser/page-and-post-restriction/tags/1.6.0/page-and-post-restriction.php#L79
• https://plugins.trac.wordpress.org/browser/page-and-post-restriction?rev=3771992
• https://plugins.trac.wordpress.org/changeset/3771992/page-and-post-restriction/trunk/page-and-post-restriction.php
• https://www.wordfence.com/threat-intel/vulnerabilities/id/2785a4e1-64f3-4b20-b0b3-7030bd88438c?source=cve

Original description

The Page and Post Restriction plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 1.6.1 This is due to the `papr_restrict_page_post_rest_api()` function, hooked on `rest_pre_dispatch`, re-authenticating the current user from the `wordpress_logged_in` cookie via `wp_set_current_user()` for any GET or HEAD REST request where the current user is 0, without verifying a REST nonce — silently undoing the nonce-zeroing that WordPress core's `rest_cookie_check_errors()` performs on cookie-authenticated requests that lack an `X-WP-Nonce` header or `_wpnonce` parameter. Combined with WordPress's permissive REST CORS behavior — which echoes the request `Origin` and sets `Access-Control-Allow-Credentials: true` — this allows an unauthenticated attacker to read REST API GET responses as a logged-in victim, exposing role-restricted and private post/page content, victim user profile data via `/wp-json/wp/v2/users/me`, and comments the victim is authorized to see. This requires the attacker to lure a logged-in user into visiting an attacker-controlled page that issues credentialed cross-origin `fetch` requests against the target site's REST API; no nonce or further victim interaction beyond the page visit is needed.