Backdoor found in widely used Linux utility breaks encrypted SSH connections
arstechnica.com
Malicious code planted in xz Utils has been circulating for more than a month.

TL;DR there was a backdoor found in the XZ program. All major distros have been updated but it is recommended that you do a fresh install on systems that are exposed to the internet and that had the bad version of the program. Only upstream distros were affected.