NULL pointer dereference in Linux kernel - CVE-2026-98537

Vulnerability identifier: #VU156839

CSH Severity: Low

CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98537

CWE-ID: CWE-476

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to potentially cause a denial of service by triggering a kernel NULL pointer dereference.

The vulnerability exists due to a NULL pointer dereference in the Linux kernel workqueue function check_flush_dependency() when checking flush dependencies for a worker that is not executing a work item. A local user can potentially trigger this condition during worker creation when memory allocation invokes an out-of-memory notifier, causing the function to dereference worker->current_pwq while it is NULL and potentially cause a denial of service.

Linux kernel
Ubuntu
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-igx (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-aws (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-nvidia-tegra (Ubuntu package) - update to 5.15.0-1070.72
linux-nvidia-tegra-igx (Ubuntu package) - update to 5.15.0-1059.59
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1070.72~20.04.1
linux (Ubuntu package) - update to 7.0.0-42.42
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-ibm (Ubuntu package) - update to 7.0.0-1017.17
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-42.42~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1017.17

• https://git.kernel.org/stable/c/0c6b9b1e295aeff1132ac7aa738148cc65f06485
• https://git.kernel.org/stable/c/1dccf5dc2f8fe688270b261ca4216e03c6a1e674
• https://git.kernel.org/stable/c/513121e69388604619ea8c0ee07e86a3d1b5b5dc
• https://git.kernel.org/stable/c/8ffececcb88262389b4f91fed0fe4884b68204bc
• https://git.kernel.org/stable/c/9bb739a5c5a570c28a62afb98e9326e2a49743c1
• https://git.kernel.org/stable/c/cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3
• https://git.kernel.org/stable/c/db6365ced4d5855e321f772b240c0e473bcfcdd5
• https://git.kernel.org/stable/c/f97e6d0572d1b39998e053732332bc3cfdd0b9aa

• NULL pointer dereference in Linux kernel kernel/workqueue.c: check_flush_dependency()
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more
• Ubuntu update for linux-nvidia-tegra, linux-nvidia-tegra-5.15, linux-nvidia-tegra-igx
• Ubuntu update for linux, linux-aws, linux-aws-5.15 and more