This week, Microsoft issued patches for 79 flaws across its platforms and products.

One of them merits particular attention: a bug so bad that Microsoft released a fix for it on Windows XP, an operating system it officially abandoned five years ago.

There’s maybe no better sign of a vulnerability’s severity; the last time Microsoft bothered to make a Windows XP fix publicly available was a little over two years ago, in the months before the WannaCry ransomware attack swept the globe.

In fact, Microsoft itself has drawn a direct parallel.

“Any future malware that exploits this vulnerability could propagate from vulnerable computer to vulnerable computer in a similar way as the WannaCry malware spread across the globe in 2017,” Simon Pope, director of incident response for the Microsoft Security Response Center, wrote in a statement announcing the patch Tuesday.

That small parcel of information, though, still gives potential attackers plenty enough to go on.

The text above is a summary, you can read full article here.