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TI-2021-10357 Aliases CVE-2021-29657GHSA-m46m-jr5m-g95h

arch/x86/kvm/svm/nested.c in the Linux kernel before 5.11.12 has a use-after-free in…

Priority LOW 33CWE-367Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 2 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

arch/x86/kvm/svm/nested.c in the Linux kernel before 5.11.12 has a use-after-free in which an AMD KVM guest can bypass access control on host OS MSRs when there are nested guests, aka CID-a58d9166a756. This occurs because of a TOCTOU race condition associated with a VMCB12 double fetch in nested_svm_vmrun.

Why it matters now

EPSS 0.00416 36th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD
Fix Partial Red Hat: 1 advisoryRed Hat: 2 fixed, 1 without a fix

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.10 to before 5.10.28; 5.11 to before 5.11.12VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.10 to before 5.10.28; 5.11 to before 5.11.12 Vulnerable ·Linux

Remediation

Red Hat 1 advisory

  • RHSA-2021:4356 Released 2021-11-09 · Red Hat rating Moderate
    kernel security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder (v. 8) kernel-tools-libs-devel-4.18.0-348.el8
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-348.el8, kernel-4.18.0-348.el8, kernel-abi-stablelists-4.18.0-348.el8 +19

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat CodeReady Linux Builder (v. 8)Fixed RHSA-2021:4356
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2021:4356
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-2021-29657
  2. 2026-10-03 Alias added: GHSA-m46m-jr5m-g95h

References

Exploit 2

Patch 1

Advisory 2

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

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