It was discovered that bsd-mailx, an implementation of the "mail" command, had an undocumented feature which treats syntactically valid email addresses as shell commands to execute. Users who need this feature can re-enable it using the "expandaddr" in an appropriate mailrc file. This update also removes the obsolete -T option. An older security vulnerability, CVE-2004-2771, had already been addressed in the Debian"s bsd-mailx package. Note that this security update does not remove all mailx facilities for command execution, though. Scripts which send mail to addresses obtained from an untrusted source should use the "--" separator before the email addresses , or they should be changed to invoke "mail -t" or "sendmail -i -t" instead, passing the recipient addresses as part of the mail header.