Improper Initialization in Linux kernel - CVE-2026-64476

Vulnerability identifier: #VU139454

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-2026-64476

CWE-ID: CWE-665

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 state management in vfio-pci runtime power management handling when changing the disable_idle_d3 setting for devices already bound to vfio-pci variant drivers. A local user can change the sysfs module parameter and trigger unbalanced power management operations to cause a denial of service.

The issue occurs because the setting was latched globally at module initialization rather than consistently per device, creating a window where existing bound devices could operate with inconsistent power management behavior.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1011.11, 7.0.0-1014.14
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1

• https://git.kernel.org/stable/c/062b820290bcb9778e43a73597df76e9bb08acfb
• https://git.kernel.org/stable/c/332d785f9ae426eeeb92527872adf09d84101ba3
• https://git.kernel.org/stable/c/4575e9aac5336d1365138c0284773bf8da4b1fa3
• https://git.kernel.org/stable/c/654710ef3135c4546b20a903bc23a51b0c44d6c8
• https://git.kernel.org/stable/c/b98296816d31441b307ef9fa8670dcf5a55e5505
• https://git.kernel.org/stable/c/f6c67cf0051f96ba61d186731d3d9409b9927db2

• Improper Initialization in Linux kernel vfio-pci runtime power management handling
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure
• Ubuntu update for linux-azure-7.0