What is the CVSS score of CVE-2026-64172?

CVE-2026-64172 has a contested CVSS base score of 7.1 from a third party (e.g. CISA-ADP), while the vendor rates it High. vuln.today uses the vendor rating as authoritative.

Which versions of Linux Kernel are affected by CVE-2026-64172?

A kernel vulnerability affecting Linux virtualization on Hygon Family 18h processors can cause guest virtual CPUs to hang, potentially disrupting workloads running on these systems.. A patch is available.

How to fix or mitigate CVE-2026-64172?

Within 24 hours, identify all hosts running Linux kernels with KVM virtualization on Hygon Family 18h processors and confirm current kernel versions. Within 7 days, plan and stage the kernel patch update across test environments, coordinating with the virtualization team to schedule maintenance windows. Within 30 days, deploy the patched kernel to all affected production hosts with post-deployment validation of guest vCPU stability.

Linux Kernel CVE-2026-64172

EUVD-2026-45857 HIGH

2026-07-19 Linux

GHSA-4cvr-85r6-xwmj

Linux Information Disclosure Amd

High

Disputed · 7.1 Vendor: Linux

Severity by source

Sources disagree (Low–High)

Vendor (Linux) PRIMARY

7.1 HIGH

AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

vuln.today AI

6.5 MEDIUM

Local guest execution is required (AV:L, PR:L for guest-level access); guest activity hangs host-scheduled vCPUs (S:C), with availability-only impact and no confidentiality or integrity effect.

3.1 AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

4.0 AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L

SUSE

5.5 MEDIUM

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Red Hat

5.5 LOW

qualitative

vuln.today treats the vendor’s rating as authoritative. A higher third-party CVSS (e.g. CISA-ADP) is shown for transparency but does not drive the headline severity.

CVSS VectorVendor: Linux

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Generated

Jul 20, 2026 - 17:47 vuln.today

CVSS changed

Jul 20, 2026 - 15:22 NVD

7.1 (HIGH)

Patch available

Jul 19, 2026 - 17:03 EUVD

CVE Published

Jul 19, 2026 - 15:40 cve.org

UNKNOWN (no severity yet)

CVE Published

Jul 19, 2026 - 15:40 cve.org

HIGH 7.1

DescriptionCVE.org

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.

AnalysisAI

Denial of service in the Linux kernel's KVM/SVM AVIC (Advanced Virtual Interrupt Controller) IPI virtualization affects Hygon Family 18h hosts, where a hardware erratum (#1235, shared with AMD Zen1 Family 17h) lets the CPU read a stale IsRunning bit during ICR write emulation and skip the expected AVIC_IPI_FAILURE_TARGET_NOT_RUNNING VM-Exit. As a result KVM misses the wakeup of a blocking target vCPU, causing hung vCPUs and unbounded stalls in guest execution. EPSS is low (0.17%, 6th percentile) and there is no public exploit identified at time of analysis; the fix disables AVIC IPI virtualization on these CPUs so every non-self IPI is correctly emulated via VM-Exit.

Technical ContextAI

The affected subsystem is KVM's AMD SVM (Secure Virtual Machine) support for AVIC, the hardware-accelerated APIC virtualization that offloads inter-processor interrupt (IPI) delivery from the hypervisor. AVIC maintains a Physical ID table with an IsRunning bit per vCPU; when a guest writes the ICR (Interrupt Command Register) to send an IPI to a not-running target, hardware is supposed to generate an AVIC_IPI_FAILURE_TARGET_NOT_RUNNING VM-Exit so KVM can wake the sleeping target vCPU. Erratum #1235 means the sender's core may read a stale IsRunning=1 and silently omit that VM-Exit. Hygon Family 18h is derived from AMD Family 17h (Zen1) silicon and inherits the same defect, so the existing Family 17h workaround is extended to Hygon. With IPI virtualization disabled KVM never sets IsRunning=1, forcing a VM-Exit for every non-self IPI. CPE data lists cpe:2.3:a:linux:linux, i.e. the mainline Linux kernel; CWE is not assigned but the behavior is a missed-wakeup/lost-event availability condition (functionally a race/synchronization defect rather than the 'Information Disclosure' tag applied by one feed).

RemediationAI

Vendor-released patch: update to a fixed Linux kernel build - stable 6.18.34, 7.0.11, or 7.1, or any distribution kernel that backports mainline commit 94ade38f317ea086a181db0e6b69c574b3b70a5e (git.kernel.org/stable/c/94ade38f317ea086a181db0e6b69c574b3b70a5e, with parallel stable commits 9560e6fee887a9594a89fa265b5b9c79b1591803 and 9a12fa5213cfc391e0eed63902d3be98f0913765). The fix simply extends the existing Family 17h erratum #1235 handling to disable AVIC IPI virtualization on Hygon Family 18h. If you cannot patch immediately and run affected Hygon hardware, a targeted workaround is to disable AVIC in the kvm_amd module (e.g. load kvm_amd with avic=0), which forces software IPI emulation and eliminates the missed-wakeup condition at the cost of losing AVIC's interrupt-delivery performance benefit for all guests on that host. This impact is limited to Hygon Family 18h hosts, so no action is needed on Intel or non-affected AMD/Hygon systems.

More in Amd

View all

CVE-2021-22986 CRITICAL Emergency POC

9.8 Mar 31

On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, and 12.

CVE-2020-6103 CRITICAL Act Now POC

9.9 Jul 20

An exploitable code execution vulnerability exists in the Shader functionality of AMD Radeon DirectX 11 Driver atidxx64.

CVE-2020-6102 CRITICAL Act Now POC

9.9 Jul 20

An exploitable code execution vulnerability exists in the Shader functionality of AMD Radeon DirectX 11 Driver atidxx64.

CVE-2020-6101 CRITICAL Act Now POC

9.9 Jul 20

An exploitable code execution vulnerability exists in the Shader functionality of AMD Radeon DirectX 11 Driver atidxx64.

CVE-2020-6100 CRITICAL Act Now POC

9.9 Jul 20

An exploitable memory corruption vulnerability exists in AMD atidxx64.dll 26.20.15019.19000 graphics driver. Rated criti

CVE-2018-6546 CRITICAL Act Now POC

9.8 Apr 13

plays_service.exe in the plays.tv service before 1.27.7.0, as distributed in AMD driver-installation packages and Gaming

CVE-2021-3653 HIGH This Week POC

8.8 Sep 29

A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. Rated high severity (CVSS 8.8), this vu

CVE-2020-12138 HIGH This Week POC

8.8 Apr 27

AMD ATI atillk64.sys 5.11.9.0 allows low-privileged users to interact directly with physical memory by calling one of se

CVE-2019-5098 HIGH This Week POC

8.6 Dec 05

An exploitable out-of-bounds read vulnerability exists in AMD ATIDXX64.DLL driver, version 26.20.13001.29010. Rated high

CVE-2015-7724 HIGH This Week POC

7.8 Jun 07

AMD fglrx-driver before 15.9 allows local users to gain privileges via a symlink attack. Rated high severity (CVSS 7.8),

CVE-2015-7723 HIGH This Week POC

7.8 Jun 07

AMD fglrx-driver before 15.7 allows local users to gain privileges via a symlink attack. Rated high severity (CVSS 7.8),

CVE-2023-1048 HIGH This Week POC

7.8 Feb 26

A vulnerability, which was classified as critical, has been found in TechPowerUp Ryzen DRAM Calculator 1.2.0.5.sys. Rate

Same technique Information Disclosure

View all

CVE-2019-2725 CRITICAL POC

9.8

CVE-2021-34523 CRITICAL POC

9.0

CVE-2013-2251 CRITICAL POC

9.8

CVE-2017-5638 CRITICAL POC

9.8

CVE-2025-24813 CRITICAL POC

9.8

CVE-2015-1701 HIGH POC

7.8

CVE-2017-0147 HIGH POC

7.5

CVE-2014-6324 HIGH POC

8.8

Vendor StatusVendor

SUSE

Severity: Moderate

Product	Status
SUSE Linux Enterprise Desktop 15 SP7	Not-Affected
SUSE Linux Enterprise Desktop 15 SP7	Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7	Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7	Not-Affected
SUSE Linux Enterprise High Availability Extension 16.0	Not-Affected

CVE-2026-64172 vulnerability details – vuln.today

Back

Linux Kernel CVE-2026-64172

Severity by source

CVSS VectorVendor: Linux

Lifecycle Timeline

DescriptionCVE.org

AnalysisAI

Technical ContextAI

RemediationAI

More in Amd

Same technique Information Disclosure

Vendor StatusVendor

SUSE

Share

External POC / Exploit Code