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.