The G/PGP (GPG) Plugin 2.1 and earlier for Squirrelmail allow remote authenticated users to execute arbitrary commands via shell metacharacters in (1) the fpr parameter to the deleteKey function in gpg_keyring.php, as called by (a) import_key_file.php, (b) import_key_text.php, and (c) keyring_main.php; and (2) the keyserver parameter to the gpg_recv_key function in gpg_key_functions.php, as called by gpg_options.php. NOTE: this issue may overlap CVE-2007-3636.
https://www.exploit-db.com/exploits/4173
https://exchange.xforce.ibmcloud.com/vulnerabilities/35364
https://exchange.xforce.ibmcloud.com/vulnerabilities/35355
http://www.vupen.com/english/advisories/2007/2513
http://www.securityfocus.com/bid/24874
http://www.securityfocus.com/archive/1/473370/100/0/threaded
http://www.attrition.org/pipermail/vim/2007-July/001710.html
http://security.gentoo.org/glsa/glsa-200708-08.xml
http://secunia.com/advisories/26424
http://secunia.com/advisories/26035
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=331
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=329