CVE-2009-4018: PHP

High severity, CVSS 7.5. EPSS: 11.3% chance of exploitation in the next 30 days.

The proc_open function in ext/standard/proc_open.c in PHP before 5.2.11 and 5.3.x before 5.3.1 does not enforce the (1) safe_mode_allowed_env_vars and (2) safe_mode_protected_env_vars directives, which allows context-dependent attackers to execute programs with an arbitrary environment via the env parameter, as demonstrated by a crafted value of the LD_LIBRARY_PATH environment variable.

Affected products

• PHP PHP: up to and including 5.2.10; version 1.0 only; version 2.0 only; version 2.0b10 only; version 3.0 only; version 3.0.1 only; …

Published 2009-11-29. Last modified 2026-06-16.