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.

In PHP versions 8.1.* before 8.1.30, 8.2.* before 8.2.24, 8.3.* before 8.3.12, when using a certain non-standard configurations of Windows codepages, the fixes for  CVE-2024-4577 https://github.com/advisories/GHSA-vxpp-6299-mxw3  may still be bypassed and the same command injection related to Windows "Best Fit" codepage behavior can be achieved. This 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.