CVE-2024-4577: PHP-CGI OS Command Injection Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2024-06-12. EPSS: 100% chance of exploitation in the next 30 days.

In PHP versions 8.1.* before 8.1.29, 8.2.* before 8.2.20, 8.3.* before 8.3.8, when using Apache and PHP-CGI on Windows, if the system is set up to use certain code pages, Windows may use "Best-Fit" behavior to replace characters in command line given to Win32 API functions. PHP CGI module may misinterpret those characters as PHP options, which may allow a malicious user to pass options to PHP binary being run, and thus reveal the source code of scripts, run arbitrary PHP code on the server, etc.

Affected products

• Fedoraproject Fedora: version 39 only; version 40 only
• PHP PHP: from 8.1.0, before 8.1.29 (fixed in 8.1.29); from 8.2.0, before 8.2.20 (fixed in 8.2.20); from 8.3.0, before 8.3.8 (fixed in 8.3.8)

Published 2024-06-09. Last modified 2026-06-17.