CVE-2021-29657: Use After Free
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 nestedsvmvmrun.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2021-29657?
CVE-2021-29657 has a high severity rating due to its potential to allow an AMD KVM guest to bypass access control on host OS MSRs.
How do I fix CVE-2021-29657?
To address CVE-2021-29657, update to Linux kernel version 5.10.223-1, 5.10.234-1, 6.1.123-1, 6.1.128-1, 6.12.12-1, or 6.12.17-1.
Which Linux kernel versions are affected by CVE-2021-29657?
Affected versions of the Linux kernel range from version 5.10 to 5.11.12.
What type of vulnerability is CVE-2021-29657?
CVE-2021-29657 is classified as a use-after-free vulnerability that is exploited through a race condition in nested virtualization.
What systems are impacted by CVE-2021-29657?
CVE-2021-29657 primarily impacts systems running KVM with nested virtualization using affected versions of the Linux kernel.