XZ Utils is free general-purpose data compression software with a high compression ratio.
A backdoor has been discovered in XZ utils. Please review the CVE identifier referenced below for details.
Our current understanding of the backdoor is that is does not affect Gentoo systems, because 1. the backdoor only appears to be included on specific systems and Gentoo does not qualify; 2. the backdoor as it is currently understood targets OpenSSH patched to work with systemd-notify support. Gentoo does not support or include these patches; Analysis is still ongoing, however, and additional vectors may still be identified. For this reason we are still issuing this advisory as if that will be the case.
There is no known workaround at this time.
All XZ utils users should downgrade to the latest version before the backdoor was introduced:
# emerge --sync
# emerge --ask --oneshot --verbose "<app-arch/xz-utils-5.6.0"