Microsoft on Wednesday issued one of its first Microsoft Security Advisories, responding to reports of a flaw in Windows that could allow DoS attacks.

In the advisory, Microsoft acknowledges the issue. The software giant also says that the problem was fixed with a patch it released in April and that systems running Windows XP with Service Pack 2 and that Windows Server with Service Pack 1 are not vulnerable.

The Microsoft Security Advisory is part of a pilot programme that Microsoft announced earlier this month. The advisory service is meant to confirm reports of flaws and provide information on how users can protect themselves, either by pointing to patches or providing a workaround.

In Wednesday's advisory, Microsoft responds to reports from French Security Incident Response Team, or FrSIRT, about a flaw in Microsoft's TCP/IP implementation.

An attacker could exploit the flaw to disrupt network connectivity, Microsoft acknowledges. However, the firm is unaware of any attacks that exploit the vulnerability and has not had reports of any customer impact, according to the advisory.

"We do not consider this to be a significant threat to the security of the Internet," Microsoft said in its advisory.