CVE-2021-4093

Public Exploit

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.

References

Link	Tags
https://bugzilla.redhat.com/show_bug.cgi?id=2028584	patch third party advisory issue tracking
https://bugs.chromium.org/p/project-zero/issues/detail?id=2222	patch mailing list exploit third party advisory

Frequently Asked Questions

What is the severity of CVE-2021-4093?: CVE-2021-4093 has been scored as a high severity vulnerability.
How to fix CVE-2021-4093?: To fix CVE-2021-4093, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-4093 being actively exploited in the wild?: It is possible that CVE-2021-4093 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-4093?: CVE-2021-4093 affects n/a kernel.

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Description

Category

CWE-125 – Out-of-bounds Read

References

Frequently Asked Questions