CVE-2021-4093
high
CVSS v3
—
CVSS v2
—
VIR risk
8.0
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.
Predictions
Exploit likelihood
20%
Patch ETA
—
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-4093
Vendor advisory: rocky — https://errata.rockylinux.org/RLSA-2022:1988
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| rocky | 8 | fixed | |
| debian | bookworm | fixed | 5.14.16-1 |
| debian | bullseye | fixed | 0 |
| debian | forky | fixed | 5.14.16-1 |
| debian | sid | fixed | 5.14.16-1 |
| debian | trixie | fixed | 5.14.16-1 |
References
Verify integrity in audit chain (admin only). AS-IS.