Microsoft has said it may release an out-of-cycle patch for a recently discovered flaw in Windows Vista and Windows Server.
Microsoft has issued five critical bulletins to address problems in its software in its latest Patch Tuesday release.
Flaws in Windows 2000, Windows XP, Windows Vista, and Windows Server have been fixed by the patches.
Some of the vulnerabilities could allow a hacker to take control of a system remotely and surfers are advised to visit the Windows Update website as soon as possible or to enable Automatic Updates on their system.
Another flaw which was discovered in Windows Vista and Windows Server has caused Microsoft further headaches.
The software vendor is concerned that information about the vulnerability has been circulated widely on the web but was not communicated to Microsoft quickly enough.
This means that no patch has yet been issued for this flaw and Microsoft suggested that it is serious enough to warrant an out-of-cycle fix.
"Microsoft is concerned that this new report of a vulnerability was not responsibly disclosed, potentially putting computer users at risk," Microsoft said in a statement.
"We continue to encourage responsible disclosure of vulnerabilities. We believe the commonly accepted practice of reporting vulnerabilities directly to a vendor serves everyone's best interests," the statement continued.