Microsoft is urging computer users to patch their systems now against a critical vulnerability that could be exploited by a fast-moving worm.

The vulnerability (CVE-2019-0708) is in Remote Desktop Services (formerly known as Terminal Services), and although Microsoft says it has not yet seen any malicious hackers exploiting the flaw it believes that it is “highly likely” it will be incorporated into malware.

And that, potentially, is a big problem because of the rapid speed with which a worm can spread.

As Microsoft’s advisory explains:

“This vulnerability is pre-authentication and requires no user interaction. In other words, the vulnerability is ‘wormable’, meaning that 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.”

Vulnerable versions of Windows include Windows 7, Windows Server 2008 R2, and Windows Server 2008 – all of which are still officially supported by Microsoft, and for which security patches are available.

However, you can tell just how serious Microsoft believes the wormable vulnerability to be because it has also issued fixes for operating systems that the company no longer officially supports: Windows XP SP3 x86, Windows XP Professional x64 Edition SP2, Windows XP Embedded SP3 x86, Windows Server 2003 SP2 x86, Windows Server 2003 x64 Edition SP2.

Yes, you thought Windows XP was dead (and good riddance, by the way). But no, Microsoft is so worried that another WannaCry-style worm outbreak might be around the corner, fuelled by out-of-date computers that are still riskily connected to the internet, that it will even roll out a patch for Windows XP.

Five years after Microsoft sounded the death knell for Windows XP, the occasional critical patch is still being produced.

Of course, Microsoft would still prefer you upgraded if at all possible to a more modern operating system. Users running Windows 8 and Windows 10 are not affected by this vulnerability.

And it’s worth pointing out that this isn’t the only patch that Microsoft users should be applying to their systems right now. Yesterday happened to be “Patch Tuesday”, the time each month when Microsoft releases monthly security updates for its software.

In this month’s bundle of security updates, Microsoft addressed a grand total of 79 vulnerabilities in its Windows operating systems and other products – the biggest number of fixes it has released in one go so far this year, with 22 vulnerabilities flagged as “Critical”, and 56 rated “Important”.

Not to be left out, Adobe has issued security patches that address 84 vulnerabilities in Adobe Reader, and one for Adobe Flash Player.

The Microsoft and Adobe vulnerabilities are serious problems that could potentially impact a large number of users. It’s important that you update your systems at your earliest opportunity, and consider enabling automatic updates if you haven’t already configured your computer to stay up-to-date.

While the world is going crazy about a WhatsApp flaw that has already been patched, and seems to have only impacted a tiny handful of targeted users, these Microsoft and Adobe software vulnerabilities could be a much bigger problem.