Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 5.10, < 5.10.28 |
Related Weaknesses (CWE)
References
- http://packetstormsecurity.com/files/163324/KVM-nested_svm_vmrun-Double-Fetch.htThird Party AdvisoryVDB Entry
- https://bugs.chromium.org/p/project-zero/issues/detail?id=2177ExploitMailing ListPatch
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.12ExploitPatchVendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a5PatchThird Party Advisory
- https://security.netapp.com/advisory/ntap-20210902-0008/Third Party Advisory
- http://packetstormsecurity.com/files/163324/KVM-nested_svm_vmrun-Double-Fetch.htThird Party AdvisoryVDB Entry
- https://bugs.chromium.org/p/project-zero/issues/detail?id=2177ExploitMailing ListPatch
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.12ExploitPatchVendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a5PatchThird Party Advisory
- https://security.netapp.com/advisory/ntap-20210902-0008/Third Party Advisory
FAQ
What is CVE-2021-29657?
CVE-2021-29657 is a vulnerability with a CVSS score of 7.4 (HIGH). 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...
How severe is CVE-2021-29657?
CVE-2021-29657 has been rated HIGH with a CVSS base score of 7.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-29657?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.