nxapplet.jar in No Machine NX Web Companion 3.x and earlier does not properly verify the authenticity of updates, which allows user-assisted remote attackers to execute arbitrary code via a crafted (1) SiteUrl or (2) RedirectUrl parameter that points to a Trojan Horse client.zip update file.
https://exchange.xforce.ibmcloud.com/vulnerabilities/72712
http://secunia.com/advisories/47685
http://archives.neohapsis.com/archives/fulldisclosure/2012-01/0466.html
http://archives.neohapsis.com/archives/bugtraq/2012-01/0161.html