A government office has warned people to stop using all versions of Internet Explorer until Microsoft issues a patch.
Germany's Federal Office for Information Security claims there are flaws in Internet Explorer that allow malware to infect a computer running using the browser.
The news comes after it was revealed last week that Internet Explorer allowed hackers in China to bypass Google's security.
The Federal Office for Information Security said in a statement that it "recommends a switch, until the existence of a patch, from Microsoft to an alternative browser".
Microsoft has said that the security problems can be fixed by setting Internet Explorer's security to "high". However, this feature renders some legitimate websites inaccessible.
In a report issued four days ago looking into the security flaw, Microsoft said, "An attacker who successfully exploited this vulnerability could gain the same user rights as the local user."
The software company said it may release a fix for this issue through the Windows Update service over the next month.
Thomas Baumgaertner, a spokesman for Microsoft in Germany, said, "There is no threat to the general user, consequently we do not support this warning."