Security Experts:

Microsoft Investigating Windows 7 Vulnerability Reported as "Highly Critical"

A report is circulating about a new Windows 7 bug that could be leveraged by attackers to run malicious code.

Microsoft told SecurityWeek that it is looking into the bug. A researcher named webDEVIL posted on Twitter that the issue could be exploited via an iFrame, resulting in the infamous blue screen of death. Vulnerability management vendor Secunia confirmed the bug, and followed up with an advisory of its own. It classified the issue as “Highly Critical.”

“The vulnerability is caused due to an error in win32k.sys and can be exploited to corrupt memory via e.g. a specially crafted web page containing an IFRAME with an overly large "height" attribute viewed using the Apple Safari browser,” according to Secunia. “Successful exploitation may allow execution of arbitrary code with kernel-mode privileges.”

The vulnerability is confirmed on a fully-patched Windows 7 Professional 64-bit OS, the firm added, noting that other versions may be affected as well.

“We are currently examining the issue and will take appropriate action to help ensure customers are protected," Jerry Bryant, group manager of response communications for Microsoft’s Trustworthy Computing Group, said in a statement.

Earlier this month, Microsoft released a hefty Patch Tuesday update to address 19 separate security bugs. Barring an out-of-band release of a patch for this or some other vulnerability before January, the company would have released a total of 99 security bulletins for the year, down 7 from 2010.