CVE-2021-29657

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.

CVSS v3.1

7.4 HIGHCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0

6.9 MEDIUMAV:L/AC:M/Au:N/C:C/I:C/A:C

EPSS

0.41% chance of exploitation in the next 30 days, 34th percentile

Published

2021-07-22

Updated

2024-08-03

Proof-of-concept exploits (1)

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

References

• CVE Record
• NVD entry

Related

• CVE-2021-29643
• CVE-2021-29662
• CVE-2021-29641
• CVE-2021-29663
• CVE-2021-29627
• CVE-2021-29827