Best Practical Solutions RT 3.8.x before 3.8.15 and 4.0.x before 4.0.8, when GnuPG is enabled, does not ensure that the UI labels unencrypted messages as unencrypted, which might make it easier for remote attackers to spoof details of a message's origin or interfere with encryption-policy auditing via an e-mail message to a queue's address.
http://lists.bestpractical.com/pipermail/rt-announce/2012-October/000212.html