CVE-2021-4093
Last modified
CVE-2021-4093 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. 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. EPSS estimates a 0.42% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 5.11, < 5.14.16 |
| Redhat | Enterprise Linux | 8.0 |
| Fedoraproject | Fedora | 35 |
| Canonical | Ubuntu Linux | 20.04 |
| Canonical | Ubuntu Linux | 21.10 |
References
- https://bugs.chromium.org/p/project-zero/issues/detail?id=2222Exploit, Mailing List, Patch, Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2028584Issue Tracking, Patch, Third Party Advisory
- https://bugs.chromium.org/p/project-zero/issues/detail?id=2222Exploit, Mailing List, Patch, Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2028584Issue Tracking, Patch, Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
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