The (1) session_save_path, (2) ini_set, and (3) error_log functions in PHP 4.4.7 and earlier, and PHP 5 5.2.3 and earlier, when invoked from a .htaccess file, allow remote attackers to bypass safe_mode and open_basedir restrictions and possibly execute arbitrary commands, as demonstrated using (a) php_value, (b) php_flag, and (c) directives in .htaccess.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6056
https://exchange.xforce.ibmcloud.com/vulnerabilities/39403
https://exchange.xforce.ibmcloud.com/vulnerabilities/35102
http://www.vupen.com/english/advisories/2008/0924/references
http://www.vupen.com/english/advisories/2008/0398
http://www.vupen.com/english/advisories/2008/0059
http://www.vupen.com/english/advisories/2007/3023
http://www.securityfocus.com/bid/25498
http://www.securityfocus.com/bid/24661
http://www.securityfocus.com/archive/1/491693/100/0/threaded
http://www.securityfocus.com/archive/1/472343/100/0/threaded
http://www.php.net/releases/5_2_5.php
http://www.php.net/releases/5_2_4.php
http://www.php.net/releases/4_4_8.php
http://www.php.net/ChangeLog-5.php#5.2.5
http://www.php.net/ChangeLog-5.php#5.2.4
http://www.php.net/ChangeLog-4.php
http://www.openwall.com/lists/oss-security/2020/09/17/3
http://www.gentoo.org/security/en/glsa/glsa-200710-02.xml
http://slackware.com/security/viewer.php?l=slackware-security&y=2008&m=slackware-security.335136
http://securityreason.com/achievement_exploitalert/9
http://secunia.com/advisories/30040
http://secunia.com/advisories/29420
http://secunia.com/advisories/28936
http://secunia.com/advisories/28750
http://secunia.com/advisories/28318
http://secunia.com/advisories/27648
http://secunia.com/advisories/27377
http://secunia.com/advisories/27102
http://secunia.com/advisories/26838
http://secunia.com/advisories/26822
http://secunia.com/advisories/26642
http://seclists.org/fulldisclosure/2020/Sep/34
http://lists.apple.com/archives/security-announce/2008/Mar/msg00001.html