CVE-2026-98399

Received Received - Intake

Null Pointer Dereference in Linux Kernel s390 IPL

Publication date: 2026-10-14

Last updated on: 2026-10-19

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: s390/ipl: Fix NULL deref in dump_reipl without re-IPL parm block Unlike kdump, which passes the re-IPL parameter block through os_info, the stand-alone dump passes it through the IPL parm block address and checksum in lowcore. Some IPL types, like HMC FTP boot or QEMU direct kernel boot, might not provide an IPL parameter block. In this case reipl_type_init() selects IPL_TYPE_UNKNOWN and reipl_block_actual remains NULL. Nevertheless, dump_reipl_run() unconditionally dereferences it when preparing the lowcore fields. This may happen to work by chance when address zero contains readable lowcore data. A zero IPL parameter block address is then stored in lowcore, causing the stand-alone dumper to enter disabled wait after completing the dump. Explicitly store a zero IPL parameter block address and checksum when no re-IPL parameter block is available. This does not change the behavior: the stand-alone dumper completes the dump and halts, while valid re-IPL parameter blocks continue to be handled as before.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-14

Last Modified

2026-10-19

Generated

2026-10-19

AI Q&A

2026-10-15

EPSS Evaluated

2026-10-18

NVD

CVE-2026-98399

EUVD

EUVD-2026-101048

Affected Vendors & Products

Vendor	Product	Version / Range
Linux	Linux	099b765139929efdcf232f8870804accf8c4cdc5
Linux	Linux	099b765139929efdcf232f8870804accf8c4cdc5
Linux	Linux	099b765139929efdcf232f8870804accf8c4cdc5
Linux	Linux	099b765139929efdcf232f8870804accf8c4cdc5
Linux	Linux	099b765139929efdcf232f8870804accf8c4cdc5
Linux	Linux	2.6.30

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability is in the Linux kernel's s390/ipl component. It involves a NULL pointer dereference in the dump_reipl function when no re-IPL parameter block is provided. The issue occurs because dump_reipl_run unconditionally dereferences reipl_block_actual even when it is NULL, which can lead to a system crash or unexpected behavior during system dumps.

Detection Guidance

This vulnerability is specific to the Linux kernel's s390 architecture and involves a NULL dereference in the dump_reipl function. Detection requires checking the kernel version and examining the s390 IPL parameter block handling. No direct network detection commands are applicable. Review kernel logs for crashes or hangs during dump operations, particularly on s390 systems.

Impact Analysis

This vulnerability may cause the system to crash or enter a disabled wait state after completing a dump if no re-IPL parameter block is available. This could lead to data loss, system unavailability, or require a manual reboot to recover.

Compliance Impact

This vulnerability does not directly affect compliance with standards like GDPR or HIPAA. It is a low-level Linux kernel issue related to IPL parameter handling during system dumps, which does not involve data processing, storage, or privacy concerns relevant to these regulations.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve the NULL dereference issue in dump_reipl without re-IPL parameter block.

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