Description of problem: PHP 5.2.3 release: http://www.php.net/releases/5_2_3.php Fixed ext/filter Email Validation Vulnerability (MOPB-45 by Stefan Esser, CVE-2007-1900)
The ext/filter extension is not included in the version of PHP distributed in Red Hat Enterprise Linux v2.1, v3, v4 or v5, nor in Red Hat Application Stack v1.