CVE-2021-4093

NameCVE-2021-4093
DescriptionA flaw was found in the KVM's AMD code for supporting the Secure Encrypted Virtualization-Encrypted State (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kernel via a malicious VMGEXIT for a string I/O instruction (for example, outs or ins) using the exit reason SVM_EXIT_IOIO. This issue results in a crash of the entire system or a potential guest-to-host escape scenario.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)stretch4.9.228-1fixed
stretch (security)4.9.320-2fixed
buster4.19.235-1fixed
buster (security)4.19.232-1fixed
bullseye5.10.106-1fixed
bullseye (security)5.10.120-1fixed
bookworm, sid5.18.5-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcestretch(not affected)
linuxsourcebuster(not affected)
linuxsourcebullseye(not affected)
linuxsource(unstable)5.14.16-1

Notes

[bullseye] - linux <not-affected> (Vulnerable code not present)
[buster] - linux <not-affected> (Vulnerable code not present)
[stretch] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/95e16b4792b0429f1933872f743410f00e590c55 (5.15-rc7)
https://bugzilla.redhat.com/show_bug.cgi?id=2028584

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