Vulnerability Description
A flaw was found in the KVM's AMD code for supporting the Secure Encrypted Virtualization-Encrypted State (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kernel via a malicious VMGEXIT for a string I/O instruction (for example, outs or ins) using the exit reason SVM_EXIT_IOIO. This issue results in a crash of the entire system or a potential guest-to-host escape scenario.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 5.11, < 5.14.16 |
| Redhat | Enterprise Linux | 8.0 |
| Fedoraproject | Fedora | 35 |
| Canonical | Ubuntu Linux | 20.04 |
Related Weaknesses (CWE)
References
- https://bugs.chromium.org/p/project-zero/issues/detail?id=2222ExploitMailing ListPatch
- https://bugzilla.redhat.com/show_bug.cgi?id=2028584Issue TrackingPatchThird Party Advisory
- https://bugs.chromium.org/p/project-zero/issues/detail?id=2222ExploitMailing ListPatch
- https://bugzilla.redhat.com/show_bug.cgi?id=2028584Issue TrackingPatchThird Party Advisory
FAQ
What is CVE-2021-4093?
CVE-2021-4093 is a vulnerability with a CVSS score of 8.8 (HIGH). A flaw was found in the KVM's AMD code for supporting the Secure Encrypted Virtualization-Encrypted State (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kern...
How severe is CVE-2021-4093?
CVE-2021-4093 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-4093?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel, Redhat Enterprise Linux, Fedoraproject Fedora, Canonical Ubuntu Linux.