CVE-2021-29657
medium
CVSS v3
—
CVSS v2
—
VIR risk
5.5
Description
arch/x86/kvm/svm/nested.c in the Linux kernel before 5.11.12 has a use-after-free in which an AMD KVM guest can bypass access control on host OS MSRs when there are nested guests, aka CID-a58d9166a756. This occurs because of a TOCTOU race condition associated with a VMCB12 double fetch in nested_svm_vmrun.
Predictions
Exploit likelihood
20%
Patch ETA
—
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-29657
Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2021-29657.html
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| arch | fixed | 5.11.13.hardened1-1 | |
| sles | affected | | |
| debian | bookworm | fixed | 5.10.28-1 |
| debian | bullseye | fixed | 5.10.28-1 |
| debian | forky | fixed | 5.10.28-1 |
| debian | sid | fixed | 5.10.28-1 |
| debian | trixie | fixed | 5.10.28-1 |
References
Verify integrity in audit chain (admin only). AS-IS.