The (1) file_exists and (2) imap_reopen functions in PHP before 5.1.5 do not check for the safe_mode and open_basedir settings, which allows local users to bypass the settings. NOTE: the error_log function is covered by CVE-2006-3011, and the imap_open function is covered by CVE-2006-1017.
http://secunia.com/advisories/21546
http://secunia.com/advisories/21768
http://secunia.com/advisories/21842
http://secunia.com/advisories/22039
http://www.mandriva.com/security/advisories?name=MDKSA-2006:162
http://www.novell.com/linux/security/advisories/2006_52_php.html
http://www.php.net/release_5_1_5.php