KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235) (CVE-2026-64172) | HOL Guard CVE

High · CVSS 7.1CVE-2026-64172

KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235)

Answer in brief

CVE-2026-64172 records a High severity (CVSS 7.1) vulnerability in KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jul 19, 2026Updated Aug 13, 2026Source checked Sep 20, 2026First seen by HOL Aug 5, 2026Material review Aug 13, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.1
Exploitation: Not marked as known exploited
Affected software: 7 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
Product	Affected versions	Fixed versions
cpe:2.3:o:linux:linux_kernel::::::::	Not reported	Not reported
cpe:2.3:o:linux:linux_kernel:7.1:rc1::::::	Not reported	Not reported
cpe:2.3:o:linux:linux_kernel:7.1:rc2::::::	Not reported	Not reported
cpe:2.3:o:linux:linux_kernel:7.1:rc3::::::	Not reported	Not reported
cpe:2.3:o:linux:linux_kernel:7.1:rc4::::::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=8de4a1c8164e5b2e40d1df764840a31de983f40b <94ade38f317ea086a181db0e6b69c574b3b70a5e \|\| >=8de4a1c8164e5b2e40d1df764840a31de983f40b <9560e6fee887a9594a89fa265b5b9c79b1591803 \|\| >=8de4a1c8164e5b2e40d1df764840a31de983f40b <9a12fa5213cfc391e0eed63902d3be98f0913765	94ade38f317ea086a181db0e6b69c574b3b70a5e, 9560e6fee887a9594a89fa265b5b9c79b1591803, 9a12fa5213cfc391e0eed63902d3be98f0913765
Linux/Linuxgeneric	6.17	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 94ade38f317ea086a181db0e6b69c574b3b70a5e if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jul 19, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 5, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235) Hygon Family 18h CPUs are derived from AMD Family 17h (Zen1) silicon and share the same erratum #1235: hardware may read a stale IsRunning=1 bit during ICR write emulation and silently fail to generate an AVIC_IPI_FAILURE_TARGET_NOT_RUNNING VM-Exit on the sending vCPU. The absence of the VM-Exit causes KVM to miss the required wakeup of blocking target vCPUs, leading to hung vCPUs and unbounded delays in guest execution. Extend the existing AMD Family 17h erratum #1235 workaround to also cover Hygon Family 18h. With IPI virtualization disabled, KVM never sets IsRunning=1 in the Physical ID table, so every non-self IPI generates a VM-Exit and is correctly emulated.

Quoted source text, attributed separately from HOL analysis.