Tag

PHP

Security

CVE-2026-2599 : Unauthenticated PHP Object Injection → WP_HTML_Token POP Chain

A technical breakdown of CVE-2026-2599, a CVSS 9.8 Critical unauthenticated PHP Object Injection vulnerability in the "Contact Form Entries" WordPress plugin (≤ 1.4.7). The download_csv function deserializes untrusted user input without allowed_classes restrictions. When combined with WordPress 6.4.0-6.4.1, the built-in WP_HTML_Token class provides a complete all-public POP chain leading to full Remote Code Execution via two unauthenticated HTTP requests.

Mohammed Lachhab
Wed 25 March 2026