This round of kernel updates address a speculative-execution vulnerability found in all Intel processors made since 2011. Greg Kroah-Hartman says in the 5.1.2 kernel patch: "Note, this release, and the other stable releases that are all being released right now at the same time, just went out all contain patches that have only seen the "public eye" for about 5 minutes. So be forwarned, they might break things, they might not build, but hopefully they fix things. Odds are we will be fixing a number of small things in this area for the next few weeks as things shake out on real hardware and workloads." In addition to 5.1.2, stable kernels 5.0.16, 4.19.43, 4.14.119, and 4.9.176 are available. More information may be found in the Xen security advisory and this new in-kernel documentation.