The VPN downloader implementation in the WebLaunch feature in Cisco AnyConnect Secure Mobility Client 2.x before 2.5 MR6 and 3.x before 3.0 MR8 does not compare the timestamp of offered software to the timestamp of installed software, which allows remote attackers to force a version downgrade by using (1) ActiveX or (2) Java components to offer signed code that corresponds to an older software release, aka Bug ID CSCtw48681.
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120620-ac