CVE-2026-96567: MW WP Form <= 5.1.7 - Unauthenticated Stored Cross-Site Scripting via 'post_id' Parameter (via stored form-submitted post meta)
The MW WP Form plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'postid' parameter in all versions up to, and including, 5.1.7 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The CSRF gate protecting form submission (MWWPFormCsrf) is bypassable by any unauthenticated visitor who first loads the public form page to obtain a valid double-submit cookie, leaving no effective barrier to storing malicious payloads.
Affected Software
Event History
Frequently Asked Questions
Who can exploit this issue?
Any unauthenticated visitor can exploit it. An attacker can first load a public MW WP Form page to obtain the double-submit CSRF cookie, then submit a malicious post_id value without needing an account.
What conditions make a site exposed?
A site is exposed if it uses MW WP Form version 5.1.7 or earlier and has a public form page that an unauthenticated visitor can load. The vulnerable input is stored in form-submitted post metadata and later executes when a user accesses an injected page.
What is the impact after a payload is stored?
Arbitrary web script can run in the browser of users who view the affected injected page. The provided vector indicates low confidentiality and integrity impact and no direct availability impact.
How can administrators check for attempted or successful exploitation?
Review MW WP Form submission data and associated post metadata for unexpected or suspicious values in the post_id parameter. Also investigate pages that render submitted form data for injected script content or unexpected client-side behavior.