NULL pointer dereference in Linux kernel - CVE-2026-98399

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Main Vulnerability Database Vulnerabilities #VU155919

NULL pointer dereference in Linux kernel - CVE-2026-98399

Published: October 15, 2026


Vulnerability identifier: #VU155919
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-2026-98399
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a denial of service during dump-and-re-IPL processing.

The vulnerability exists due to a null pointer dereference in dump_reipl_run() when preparing lowcore fields without an available re-IPL parameter block. A local user can trigger the affected dump-and-re-IPL processing to cause a denial of service.

HMC FTP boot and QEMU direct kernel boot may leave the IPL parameter block unavailable. If address zero contains readable lowcore data, processing may continue, but the stand-alone dumper enters disabled wait after completing the dump.


Affected software

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)

How to mitigate CVE-2026-98399

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

External References

Related Security Bulletins