Surfers using Internet Explorer 7 should download and apply a patch issued by Microsoft for the browser as soon as possible.
The patch, MS09-002, covers two flaws in IE7 rated as 'critical' by Microsoft.
"The vulnerabilities could allow remote code execution if a user views a specially crafted web page using Internet Explorer," a Microsoft security advisory reads.
"Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights," the document continues.
The patch will be downloaded automatically if your PC has Automatic Updates enabled. If not, you should visit the Windows Update website and download the patch from there.
The patch was one of four issued by Microsoft on Tuesday evening in its regular 'Patch Tuesday' release.
Other patches covered problems in Exchange Server, SQL Server and Visio.
www.windowsupdate.microsoft.com