Critical security fixes are backported. There where a lot of kernels released yesterday that had the fix.
For 5.15, 5.15.122 was released with the zenbleed mitigation.
5.15.122 was released with the zen bleed mitigation
But Ubuntu users (for example) won’t get that automatically. Canonical still has to pull the upstream release, run validation, and roll out a patch. It will probably be speedy, but still on the order of several weeks before people see it by default.
Critical security fixes are backported. There where a lot of kernels released yesterday that had the fix. For 5.15, 5.15.122 was released with the zenbleed mitigation.
But Ubuntu users (for example) won’t get that automatically. Canonical still has to pull the upstream release, run validation, and roll out a patch. It will probably be speedy, but still on the order of several weeks before people see it by default.