Microsoft is rushing out patch to fix problematic security issues with its Internet Explorer 7 browser.
The security update, marked as 'critical', will be available from 6pm on 17 December.
Problems due to the security flaw have affected as many as 10,000 websites, allowing cyber-criminals to take control of people's computers and steal passwords and private data.
According to Rick Ferguson, a senior security adviser at security firm Trend Micro, told the BBC: "It is inevitable that it will be adapted by criminals. It's just a question of modifying the payload the trojan installs."
The BBC report adds that: "It is relatively unusual for Microsoft to issue what it calls an "out-of-band" security bulletin and experts are reading the decision to rush out a patch as evidence of the potential danger of the flaw."
While some security experts have suggested temporarily swopping over to alternative browsers such as Firefox, Opera, Chrome or Apple's Safari, Graham Cluley, senior consultant with security firm Sophos, reminded the BBC that:
"Firefox has issued patches and Apple has too. Whichever browser you are using you have to keep it up to date… People have to be prepared and willing to install security updates. That nagging screen asking if you want to update should not be ignored."