XZ Gets the All-Clear
The back door xz vulnerability has been officially reverted for Fedora 40 and versions 38 and 39 were never affected.
If you've been in panic mode over the xz backdoor vulnerability, fret not as it has been patched for Fedora 40 beta and Rawhide.
According to Fedora Magazine, if you applied an update to the beta or rawhide versions during the time when the compromised package was found in its repositories, the current update is now reverted, so version 5.4.6 should be installed.
Fedora Magazine also goes on to mention that the SSH daemon doesn't run by default, so the Workstation edition is even less at risk.
On the Ubuntu side of things, Canonical delayed the final release of Noble Numbat (version 24.04) until April 25 so they could address the problem.
Red Hat Enterprise Linux, stable Debian releases, Linux Mint, Gentoo Linux, Alpine Linux, and Amazon Linux are uaffected by the xz flaw.
As for Arch Linux, the maintainers have created this page to help users. The page includes a recent update that states, "To our knowledge, the malicious code which was distributed via the release tarball never made it into the Arch Linux provided binaries, as the build script was configured to only inject the bad code in Debian/Fedora based package build environments. The news item below can therefore mostly be ignored."
Fortunately, xz was discovered before any serious damage could occur and should serve as a cautionary tale for development teams around the globe.