Description
In the Linux kernel, the following vulnerability has been resolved:

s390/ipl: Fix NULL deref in kdump without re-IPL parm block

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.

kdump passes the re-IPL parameter block to the dump kernel through
os_info. Before commit 3b9678472bab ("s390/ipl: correct kdump reipl
block checksum calculation"), the os_info entry was added only for
IPL types which initialized reipl_block_actual. That commit moved the
os_info update to machine_crash_shutdown(), making it unconditional. As
a result, set_os_info_reipl_block() dereferences reipl_block_actual for
IPL_TYPE_UNKNOWN. This may happen to work by chance when address zero
contains readable lowcore data and the resulting empty os_info entry is
ignored by the dump kernel.

Skip the os_info update when no re-IPL parameter block is available.
Kdump then collect the dump and reboot without setting re-IPL parameter
block.
Published: 2026-10-14
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Wed, 14 Oct 2026 13:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: s390/ipl: Fix NULL deref in kdump without re-IPL parm block 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. kdump passes the re-IPL parameter block to the dump kernel through os_info. Before commit 3b9678472bab ("s390/ipl: correct kdump reipl block checksum calculation"), the os_info entry was added only for IPL types which initialized reipl_block_actual. That commit moved the os_info update to machine_crash_shutdown(), making it unconditional. As a result, set_os_info_reipl_block() dereferences reipl_block_actual for IPL_TYPE_UNKNOWN. This may happen to work by chance when address zero contains readable lowcore data and the resulting empty os_info entry is ignored by the dump kernel. Skip the os_info update when no re-IPL parameter block is available. Kdump then collect the dump and reboot without setting re-IPL parameter block.
Title s390/ipl: Fix NULL deref in kdump without re-IPL parm block
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-14T13:26:00.872Z

Reserved: 2026-09-25T10:25:14.346Z

Link: CVE-2026-98400

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-14T14:17:51.010

Modified: 2026-10-14T14:17:51.010

Link: CVE-2026-98400

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.