Microsoft plans to issue nearly a dozen security patches on Tuesday, including critical fixes for Windows and Office.

It will release six updates for the operating system and four for the office suite, according an advance notice sent out on Thursday by the software giant. Some of the patches will be deemed "critical," the company's highest severity rating. The company also plans to send out a bulleting for Microsoft .Net that will be tagged moderate, it said.

The updates, part of Microsoft's regularly scheduled monthly patch cycle, come after sample attack code has surfaced for vulnerabilities in the Windows Shell component of the operating system. Those flaws could enable attackers to use a Web site to load malicious software onto systems.

The past few weeks have seen the arrival of third-party patches for the Windows Shell problem. The Zeroday Emergency Response Team, or ZERT, delivered its own fix, aiming to help people protect their PCs until Microsoft issued an official update. In addition, security company Determina provided an outside patch for the same issue.

Microsoft has said it will provide a patch for the Windows Shell vulnerability in its October bunch of bulletins. It is expected to announce more details regarding the flaws once the patches are released next week.

In September, it delivered a critical fix for Office, one of three security bulletins in that monthly patch cycle.