IT staff await critical security update from Microsoft

IT system administrators are being warned today about a critical security vulnerability in versions of Windows, which could allow hackers to install malicious code (such as a worm) without user intervention.

According to Microsoft versions of its Windows 2000, Windows XP, Windows Server 2003, Windows Vista, and Windows Server 2008 operating system are affected by the bug – which is anticipated to be fixed by an emergency patch to be released at 10am PST (6pm UK time) today.

Microsoft announcement about out-of-band critical security update

More information can be found in Microsoft’s advance notice at

Microsoft normally bundles its security updates into a monthly package, known in the industry as “Patch Tuesday”, and it is relatively unusual for the company to issue a fix for a security vulnerability outside of this cycle. This may indicate that Microsoft considers the bug particularly important to patch as soon as possible.