CVE-2026-64172 Details
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.
A vulnerability in the Linux kernel's KVM (Kernel-based Virtual Machine) module for Hygon Family 18h CPUs has been addressed. These CPUs, derived from AMD Family 17h (Zen1), share a specific erratum (#1235) that can disrupt virtual interrupt handling. During emulation of interrupt control writes, the hardware may incorrectly read a stale 'IsRunning' bit, failing to signal when a virtual CPU is not active. This oversight prevents KVM from waking up blocked target virtual CPUs, causing them to hang and delaying guest execution. The issue has been resolved by extending the existing workaround for AMD Family 17h to also include Hygon Family 18h, ensuring proper virtualization of interrupt processing and preventing execution delays.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been addressed. Instructions for downloading the patched version are available in the Linux kernel documentation.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/94ade38f317ea086a181db0e6b69c574b3b70a5e | kernel.org | Patch |
| https://git.kernel.org/stable/c/9560e6fee887a9594a89fa265b5b9c79b1591803 | kernel.org | Patch |
| https://git.kernel.org/stable/c/9a12fa5213cfc391e0eed63902d3be98f0913765 | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| NVD-CWE-noinfo | Insufficient Information to Classify Weakness | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 6.17, < 6.18.34 >= 6.19, < 7.0.11 7.1 rc1 7.1 rc2 7.1 rc3 7.1 rc4 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Aug 13, 2026 | Initial Analysis | [email protected] |
| Jul 20, 2026 | CVE Modified | kernel.org |
| Jul 19, 2026 | New CVE Received | kernel.org |