CVE-2021-29657

high

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.

References

http://packetstormsecurity.com/files/163324/KVM-nested_svm_vmrun-Double-Fetch.html

https://bugs.chromium.org/p/project-zero/issues/detail?id=2177

https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.12

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a58d9166a756a0f4a6618e4f593232593d6df134

https://security.netapp.com/advisory/ntap-20210902-0008/

Details

Source: Mitre, NVD

Published: 2021-07-22

Risk Information

CVSS v2

Base Score: 6.9

Vector: CVSS2#AV:L/AC:M/Au:N/C:C/I:C/A:C

Severity: Medium

CVSS v3

Base Score: 7.4

Vector: CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: High