According to Peter Winter-Smith's post on Pastebin, the problem is anchored in nvvsvc.exe, a file that is used in the Nvidia display driver service. The file is reportedly is vulnerable to a buffer overflow and code injection attack. Since nvvsvc.exe runs with full system access rights, the developer claims that any program can be installed by an attacker.
While the information on how the issue can be exploited is currently freely available and the exploit code circulated by Winter-Smith, it is unclear how the exploit could target a client PC and how it could be triggered. In his test setup, he used a Dell XPS 15 system with a GT540M GPU running under Windows 7 (64-bit). He also noted that he ran the test with full administrator rights on the PC with unrestricted access to the computer.
Nvidia has not reacted to the report yet and the post on Pastebin was removed with the comment: "I'm sorry to say that I've had to remove this post - it has caused some trouble for a few friends of mine and I didn't intend for that to happen." However, the author announced his discovery on several forums and websites, including attachments with the exploit code.