Threat actors are actively exploiting a critical security flaw in Everest Forms Pro, a WordPress plugin with about 4,000 active installations, to execute arbitrary code, leading to a complete site compromise. The vulnerability in question is CVE-2026-3300 (CVSS score: 9.8), a remote code execution bug impacting all versions of the plugin up to, and including, 1.9.12. A patch for the flaw was released on March 18, 2026, with version 1.9.13. "This is due to the Calculation Addon's process_filter() function concatenating user-submitted form field values into a PHP code string without proper escaping before passing it to eval()," Wordfence said. "The sanitize_text_field() function applied to input does not escape single quotes or other PHP code context characters. This makes it possible for…