Improper locking in Linux kernel - CVE-2026-64172

Vulnerability identifier: #VU138453

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64172

CWE-ID: CWE-667

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper hardware state handling in KVM SVM AVIC IPI virtualization when emulating ICR writes on Hygon Family 18h CPUs. A local user can trigger inter-processor interrupts from a guest to cause a denial of service.

The issue can lead to hung vCPUs and unbounded delays in guest execution.

Linux kernel
Ubuntu
linux-ibm (Ubuntu package)
linux-azure (Ubuntu package)
linux-aws (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/94ade38f317ea086a181db0e6b69c574b3b70a5e
• https://git.kernel.org/stable/c/9560e6fee887a9594a89fa265b5b9c79b1591803
• https://git.kernel.org/stable/c/9a12fa5213cfc391e0eed63902d3be98f0913765

• Improper locking in Linux kernel kvm svm
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia