The helper application in Cisco AnyConnect Secure Mobility Client (formerly AnyConnect VPN Client) before 2.3.185 on Windows, and on Windows Mobile, downloads a client executable file (vpndownloader.exe) without verifying its authenticity, which allows remote attackers to execute arbitrary code via the url property to a certain ActiveX control in vpnweb.ocx, aka Bug ID CSCsy00904.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.