{"schema_version":"1.7.5","id":"CVE-2021-4093","published":"2022-02-18T18:15:10.363Z","modified":"2026-03-14T11:10:58.607129Z","details":"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.","affected":[{"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-4093.json","unresolved_ranges":[{"events":[{"introduced":"5.11"},{"fixed":"5.14.16"}]},{"events":[{"introduced":"0"},{"last_affected":"8.0"}]},{"events":[{"introduced":"0"},{"last_affected":"35"}]},{"events":[{"introduced":"0"},{"last_affected":"20.04"}]},{"events":[{"introduced":"0"},{"last_affected":"21.10"}]}]}}],"references":[{"type":"FIX","url":"https://bugs.chromium.org/p/project-zero/issues/detail?id=2222"},{"type":"FIX","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2028584"}],"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"}]}