CVE-2026-4257 Contact Form by Supsystic <= 1.7.36 - Unauthenticated Server-Side Template Injection via Prefill Functionality

The Contact Form by Supsystic plugin for WordPress is vulnerable to Server-Side Template Injection SSTI leading to Remote Code Execution RCE in all versions up to, and including, 1.7.36. This is due to the plugin using the Twig TwigLoaderString template engine without sandboxing, combined with th...