Proof-of-concept code for an unpatched vulnerability in all supported versions of Windows, including Vista, has gone public, prompting alerts from security vendors and a warning from its Russian discoverer that the flaw may be dangerous.

It is the first Windows Vista exploit made public since the operating system was released to volume license customers Nov. 30.

According Symantec and eEye Digital Security, the bug is a memory corruption vulnerability that pops up when the MessageBox function is called; eEye pegged the threat as "medium," while Symantec labeled it as a "privilege escalation," a type of threat generally considered low on the security scale. An attacker would need authorized access to a PC to exploit the bug.

TechWeb