This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Advantech WebAccess. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
The specific flaw exists within the webvact.ocx ActiveX Control. The control does not check the length of an attacker-supplied UserName string before copying it into a fixed length buffer on the stack. This allows an attacker to execute arbitrary code in the context of the browser process.