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TI-2021-02973 Aliases CVE-2021-4093GHSA-2vg6-vx3w-m2r4

Out-of-bounds read in kernel

Priority LOW 38CWE-125Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-787 and the CVSS impact.

Summary

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.

Why it matters now

EPSS 0.00419 36th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed Red Hat: 2 advisories

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
—kernelkernel 5.15—No fix listedCNA
  • kernel Vendor— Affected kernel 5.15 Fixed in — No fix listed CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.11 to before 5.14.16VulnerableLinux
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*8.0VulnerableRed Hat
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*35VulnerableFedoraproject
cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*20.04VulnerableCanonical
cpe:2.3:o:canonical:ubuntu_linux:21.10:*:*:*:*:*:*:*21.10VulnerableCanonical
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.11 to before 5.14.16 Vulnerable ·Linux
  • cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
  • cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject
  • cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:* Versions 20.04 Vulnerable ·Canonical
  • cpe:2.3:o:canonical:ubuntu_linux:21.10:*:*:*:*:*:*:* Versions 21.10 Vulnerable ·Canonical

Remediation

Red Hat 2 advisories

  • RHSA-2022:1988 Released 2022-05-10 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-372.9.1.el8, kernel-4.18.0-372.9.1.el8, kernel-abi-stablelists-4.18.0-372.9.1.el8 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-372.9.1.el8
  • RHSA-2022:1975 Released 2022-05-10 · Red Hat rating Important
    kernel-rt security and bug fix update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-372.9.1.rt7.166.el8, kernel-rt-core-4.18.0-372.9.1.rt7.166.el8, kernel-rt-debug-4.18.0-372.9.1.rt7.166.el8 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-372.9.1.rt7.166.el8, kernel-rt-core-4.18.0-372.9.1.rt7.166.el8, kernel-rt-debug-4.18.0-372.9.1.rt7.166.el8 +7

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2022:1988
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2022:1988
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2022:1975
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2022:1975
Not affected: 3 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-4093
  2. 2026-10-03 Alias added: GHSA-2vg6-vx3w-m2r4

References

Exploit 1

Patch 1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences