Microsoft released seven critical patches on Tuesday as part of its regular Patch Tuesday update cycle.

The various security bugs in Excel, Word, Microsoft Office, Internet Explorer, Microsoft Exchange, BizTalk Server, and Windows DNS Server all earned Microsoft's most severe rating.

All the vulnerabilities allow hackers to inject malicious code onto systems running vulnerable software packages, but some are more severe than others.

The flaws in Microsoft Office and Windows DNS Server are both the subject of active hacking attacks and, therefore, form the most pressing patching priority.

More details on the bugs can be found in Microsoft's summary here, or in an overview on "Black Wednesday" from the SANS Institute's Internet Storm Centre. ®

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