Microsoft is to skip next week's usual Patch Tuesday because it has no patches, said the company.

In its monthly advance notification bulletin, Microsoft simply said, "No new Microsoft Security Bulletins will be released on March 13, 2007."

It's the first time in 18 months that Microsoft has not issued at least one security update in a scheduled patch roll-out. Since January 2003, only three months have been without security fixes.

This does not mean there are no vulnerabilities waiting to be fixed. According to security organisations, there are numerous problems still unpatched. eEye's Zero-Day Tracker, for example, shows five vulnerabilities that have been reported to Microsoft but not patched. The SANS Institute's Internet Storm Center, meanwhile, lists nine bugs on its most recent “The missing Microsoft patches” chart.

However, Microsoft said it would issue several unspecified non-security, high-priority updates.

Last month, Microsoft released 12 updates that fixed 20 vulnerabilities; in January, it issued four security bulletins and patched 10 bugs.