| CVE-2021-29657 | Date: (C)2021-06-02 (M)2024-04-19 |
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 Score and Metrics +CVSS Score and Metrics -| CVSS V3 Severity: | CVSS V2 Severity: |
| CVSS Score : 7.4 | CVSS Score : 6.9 |
| Exploit Score: 1.4 | Exploit Score: 3.4 |
| Impact Score: 5.9 | Impact Score: 10.0 |
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| CVSS V3 Metrics: | CVSS V2 Metrics: |
| Attack Vector: LOCAL | Access Vector: LOCAL |
| Attack Complexity: HIGH | Access Complexity: MEDIUM |
| Privileges Required: NONE | Authentication: NONE |
| User Interaction: NONE | Confidentiality: COMPLETE |
| Scope: UNCHANGED | Integrity: COMPLETE |
| Confidentiality: HIGH | Availability: COMPLETE |
| Integrity: HIGH | |
| Availability: HIGH | |
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