NULL pointer dereference in Linux kernel - CVE-2026-98400

Vulnerability identifier: #VU155918

CSH Severity: Low

CVSS v4: 0 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98400

CWE-ID: CWE-476

Exploitation vector: Remote 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 set_os_info_reipl_block() when kdump crash shutdown processes an unavailable re-IPL parameter block. A local user can trigger the affected crash-shutdown path to cause a denial of service.

HMC FTP boot and QEMU direct kernel boot may leave the system without an IPL parameter block. The invalid access may succeed by chance if address zero contains readable lowcore data.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (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 (Ubuntu package) - update to 7.0.0-42.42
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
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/030e88812435fc5d6aa42eee41fa77b5ea620327
• https://git.kernel.org/stable/c/50f9c40768e84f30d374235b3ee3850a94d9ac29
• https://git.kernel.org/stable/c/7f918871112e8e7c581e99eb8e545af4e59c8367
• https://git.kernel.org/stable/c/92d0829eae257544b6b0faccb6e7079c45e22d48
• https://git.kernel.org/stable/c/b6bf82bc5e00afaf836f8bb9a676bffc182a6bbd

• NULL pointer dereference in Linux kernel s390 kernel
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more