Cisco Security Advisory – The IronPort PXE Encryption solution is affected by two vulnerabilities that could allow unauthorized individuals to view the contents of secure e-mail messages. To exploit the vulnerabilities, attackers must first intercept secure e-mail messages on the network or via a compromised e-mail account.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/73911/cisco-sa-20090114-ironport.txt
Source: https://packetstormsecurity.com/files/73911/Cisco-Security-Advisory-20090114-ironport.html