{"id":"CVE-2021-29657","details":"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.","modified":"2026-04-16T04:41:56.900950235Z","published":"2021-07-22T17:15:09.470Z","references":[{"type":"ADVISORY","url":"http://packetstormsecurity.com/files/163324/KVM-nested_svm_vmrun-Double-Fetch.html"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20210902-0008/"},{"type":"FIX","url":"https://bugs.chromium.org/p/project-zero/issues/detail?id=2177"},{"type":"FIX","url":"https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.12"},{"type":"FIX","url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a58d9166a756a0f4a6618e4f593232593d6df134"}],"affected":[{"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-29657.json","unresolved_ranges":[{"events":[{"introduced":"5.10"},{"fixed":"5.10.28"}]},{"events":[{"introduced":"5.11"},{"fixed":"5.11.12"}]}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}