CVE-2021-4093

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.

Bugs

• <https://bugzilla.redhat.com/show_bug.cgi?id=2028584&gt;