The helper application in Cisco AnyConnect Secure Mobility Client (formerly AnyConnect VPN Client) before 2.5.3041, and 3.0.x before 3.0.629, on Linux and Mac OS X 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 Java applet, aka Bug ID CSCsy05934.