Mitigate MS17-010 on Windows XP? (wannacry ransomware)
Microsoft released patches for all operating systems in custom support. Please see here.
For English language patches, direct links are Windows XP SP2 x64 and Windows XP SP3 x86. Localized version of the patch can be found here. Rest of the links can be found on the bottom of the blog post.
There is a MS17-010 patch for Windows XP Embedded systems that fits the regular Windows XP. You can download it at the link below:
http://catalog.update.microsoft.com/v7/site/search.aspx?q=4012598
Google for the "POSready" string to learn how to install this Windows XP Embedded patch on a regular Windows XP.