bsd-mailx - security update

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 (such as a web form) should use the
-- separator before the email addresses (which was fixed to work
properly in this update), or they should be changed to invoke
mail -t or sendmail -i -t instead, passing the
recipient addresses as part of the mail header.

For the stable distribution (wheezy), this problem has been fixed in
version 8.1.2-0.20111106cvs-1+deb7u1.

We recommend that you upgrade your bsd-mailx packages.