CVE-2011-4006
The ESMTP inspection feature on Cisco Adaptive Security Appliances (ASA) 5500 series devices with software 8.2 through 8.5 allows remote attackers to cause a denial of service (CPU consumption) via an unspecified closing sequence, aka Bug ID CSCtt32565.
Date published : 2012-05-02
http://www.cisco.com/web/software/283878312/88166/ASA-851-Interim-Release-Notes.html