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CVE-2021-29657 Detail

Current 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.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  7.4 HIGH
Vector:  CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have published a CVSS score for this CVE based on publicly available information at the time of analysis. The CNA has not provided a score within the CVE List.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://packetstormsecurity.com/files/163324/KVM-nested_svm_vmrun-Double-Fetch.html Third Party Advisory  VDB Entry 
https://bugs.chromium.org/p/project-zero/issues/detail?id=2177 Exploit  Mailing List  Patch  Third Party Advisory 
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.12 Exploit  Patch  Vendor Advisory 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a58d9166a756a0f4a6618e4f593232593d6df134 Patch  Third Party Advisory 
https://security.netapp.com/advisory/ntap-20210902-0008/ Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-416 Use After Free cwe source acceptance level NIST  
CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition cwe source acceptance level NIST  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-29657
NVD Published Date:
07/22/2021
NVD Last Modified:
10/18/2021
Source:
MITRE