NULL pointer dereference in Linux kernel - CVE-2026-64183

Vulnerability identifier: #VU138435

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-2026-64183

CWE-ID: CWE-476

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 a NULL pointer dereference in the EFI runtime workqueue handling for ACPI PRM calls when invoking EFI runtime calls during early initialization. A local user can trigger early PRM-related runtime calls to cause a denial of service.

The issue occurs when ACPI PRM accesses happen before the EFI runtime workqueue has been allocated during system initialization.

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/13c6da02e767152c9ac4330962247a5e47011035
• https://git.kernel.org/stable/c/29cd94e678fcb3c4fd0f359deeac6d61334323fc
• https://git.kernel.org/stable/c/6996e954ae830f5b793ba6cf449885ca519dbdd2
• https://git.kernel.org/stable/c/c32a1fbe0f9a48453a552bb315cc4f1e7a74084e
• https://git.kernel.org/stable/c/e871549f7894ad4114b3dd53f241aa25a268ba8b

• NULL pointer dereference in Linux kernel firmware efi driver
• 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