The following was copied/pasted from http://news.softpedia.com/news/microsoft-releases-another-surprising-windows-xp-security-update-kb982316-515938.shtml
Specifically, this new update is KB982316 and was published by Microsoft for Windows XP systems on May 19 [2017]. Even though no specifics are available, there’s a good chance this update fixes an NSA vulnerability exploited by hackers following the latest leaks from Shadow Brokers, so XP users are recommended to install it as soon as possible.
The update is only 492 KB in size and, according to Microsoft, it fixes a “security issues [that] has been identified and which could allow an authenticated local attacker to compromise your system and gain control over it.”