CVE-2026-98400

unknown

Assigned by CNA: linux

Published 2026-10-14 · Modified 2026-10-14

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CVSS v3

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CVSS v4 NEW

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not yet in upstream

VIR risk

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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.

Predictions

Exploit likelihood

20%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

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References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.