Microsoft has released two patches for its Vista OS (operating system), saying that it too is affected by flaws that were disclosed during the company's 8 August security updates.

The patches, which were released earlier this week, fix critical flaws described in Microsoft Security Bulletin MS06-042 and MS06-051. They fix bugs in Internet Explorer and the Windows kernel, and were described on Tuesday in a blog posting by Vista product manager Alex Heaton. The posting can be found here.

Vista is not affected by the most scrutinised vulnerability in this month's patches, a Windows Server service flaw that is already being exploited by some hackers. This bug prompted a rare warning from the US Department of Homeland Security last week.

The latest patches raised some eyebrows because Microsoft had not previously acknowledged that these bugs also affect Vista.

Microsoft has issued this type of patch for beta software in the past – it released a January security update for Windows Vista Beta 1.0 – but the company does not provide information about beta products in its regularly scheduled monthly updates, said Stephen Toulouse, security program manager with Microsoft's security response centre. "Beta products are not listed in the security bulletins as they are still under development and not intended to be used in production environments," he said.

Vista, however, will be "the first major Microsoft product release that will be serviced with security updates throughout the beta process", Heaton wrote.

One Microsoft observer was sceptical about the idea.

The company is setting a bad precedent by agreeing to these security updates, because it muddies the difference between supported products and those in beta test, said Russ Cooper, a senior information security analyst at CyberTrust.

He believes that Microsoft is "dead wrong to commit to providing patches of any kind for Vista beta testers, in any forum other than official beta tester channels".

The updates do provide Microsoft with one benefit, however, Cooper said. They pre-empt reports on security flaws in beta software such as those issued by Symantec over the past weeks. "Microsoft is avoiding more of that stupid Symantec publicity that says Vista has security holes," he said.

Downloads of the Vista patches can be found here.