PHP before 4.3.7 on Win32 platforms does not properly filter all shell metacharacters, which allows local or remote attackers to execute arbitrary code, overwrite files, and access internal environment variables via (1) the "%", "|", or ">" characters to the escapeshellcmd function, or (2) the "%" character to the escapeshellarg function.

References

• https://nvd.nist.gov/vuln/detail/CVE-2004-0542
• https://exchange.xforce.ibmcloud.com/vulnerabilities/16331
• http://www.idefense.com/application/poi/display?id=108
• http://www.php.net/release_4_3_7.php