| Name | CVE-2021-4093 |
| Description | A 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. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| linux (PTS) | jessie, jessie (lts) | 3.16.84-1 | vulnerable |
| stretch (security) | 4.9.320-2 | fixed |
| stretch (lts), stretch | 4.9.320-3 | fixed |
| buster (security), buster, buster (lts) | 4.19.316-1 | fixed |
| bullseye | 5.10.223-1 | fixed |
| bullseye (security) | 5.10.226-1 | fixed |
| bookworm | 6.1.115-1 | fixed |
| bookworm (security) | 6.1.119-1 | fixed |
| trixie | 6.12.5-1 | fixed |
| sid | 6.12.6-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| linux | source | jessie | (unfixed) | end-of-life | | |
| linux | source | stretch | (not affected) | | | |
| linux | source | buster | (not affected) | | | |
| linux | source | bullseye | (not affected) | | | |
| linux | source | (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