Microsoft said it hopes to have a patch ready next week to fix the most recent flaw found in its Windows program -- a flaw that could leave computers vulnerable to a virus.

The software giant said in a statement it had "completed development of a security update to fix the vulnerability" that it discovered last week. The update is being finalized and the company hopes to release it on January 10.

Microsoft added it has been monitoring any attempts to attack the vulnerability in Windows.

"Although the issue is serious and the attacks are being attempted, Microsoft's intelligence sources indicate that the scope of the attacks is limited," it said.

The flaw in the system lets computers come under attack if users visit harmful Web sites or open e-mail attachments. Until the patch is released, Microsoft said computer users should be careful not to visit unfamiliar Web sites.