This indicates an attack attempt against a Buffer Overflow vulnerability in Microsoft Windows HTTP Services (WinHTTP).
The vulnerability is caused because the vulnerable application fails to adequately sanitise user-supplied input. Attackers can exploit this to execute arbitrary code in the context of the user running the application. Successful exploits will compromise an affected system.
Windows XP Professional - sp2 (i386)
Windows XP Professional - sp3 (i386)
Windows Vista Ultimate - sp0 (i386)
Windows Vista Ultimate - sp1 (i386)
Denial of Service: Remote attackers can crash vulnerable systems.
Currently we are not aware of any vendor supplied patch for this issue.