Worries of a cumbersome global computer virus disruption have provoked Microsoft to assign security updates for quite old versions of its Windows software.
One spot is for Windows XP, whose debut was in 2001 and also Microsoft discontinued to support in 2014.
Microsoft said the application stopped a gap that could be used to reach a virus.
Malicious hackers abusing it could propel worldwide crash like the Wanna cry worm in 2017, which hit thousands of machines.
It was "extremely" the vulnerability would be hurt if it went unresolved, wrote Simon Pope, Microsoft's director of incident response, in a blog about the bug.
He further said the bug could be misused easily by correlating to a helpless machine over the web.
"Any later malware that misuses this unprotected scatter from weak computer to unsafe computer in a similar way as the WannaCry malware extended across the globe in 2017".
Although Microsoft dropped assistance for Windows XP more than five years ago, the last software spot it issued for the operating system was issued just prior to the Wanna cry outbreak.
Mr. Pope answered saying, "We firmly recommend that all affected systems… should be ungraded sooner as possible".
Further, Microsoft declared that there was no sign that cyber-thieves were currently misusing the loophole.
Well, Microsoft further added, common man and businesses using Windows 8 or 10 are not in danger,