NULL pointer dereference in Linux kernel - CVE-2026-98476

Vulnerability identifier: #VU156776

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-2026-98476

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 missing null-pointer check in ccw_device_get_util_str() in the Linux kernel s390 channel I/O subsystem when a subchannel's PMCW still references a CHPID whose channel path registry entry has been removed. A local user can trigger the affected lookup under this condition to potentially crash the kernel when the null pointer returned by chpid_to_chp() is dereferenced.

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/27e396a89f76f742abdbe9f8c4a58a6e806fdf59
• https://git.kernel.org/stable/c/44b16b02608058fc72198ac0205969f0f43065df
• https://git.kernel.org/stable/c/5b76268dac968612f7283d59b539036de955b7d9
• https://git.kernel.org/stable/c/5e006ac90a4d331db1dd712b91fec849b45ffc01
• https://git.kernel.org/stable/c/5fc54e04dad90b15d0430118b3f288a1d64e66c9
• https://git.kernel.org/stable/c/9d8b21820caed9128945fffcedf03e2a4c21eee2
• https://git.kernel.org/stable/c/c3bbcb32deecc06ebb1762398399b566d5ff2fc9
• https://git.kernel.org/stable/c/dbf30e661ceb9a52c94c85719716391dcc29142a

• NULL pointer dereference in Linux kernel s390 cio driver
• 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