CVE-2026-98399 is a vulnerability in Linux Kernel
Published on October 14, 2026
s390/ipl: Fix NULL deref in dump_reipl without re-IPL parm block
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.
Products Associated with CVE-2026-98399
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Affected Versions
Linux:- Version 099b765139929efdcf232f8870804accf8c4cdc5 and below 41647864e62b28388ecccc23a82f0e0a091f4ef2 is affected.
- Version 099b765139929efdcf232f8870804accf8c4cdc5 and below aed56fa3108b7095e6a048e134981506c056a6cb is affected.
- Version 099b765139929efdcf232f8870804accf8c4cdc5 and below 8d7988e8116c3d29d9e02ca9d37ee84577643f2d is affected.
- Version 099b765139929efdcf232f8870804accf8c4cdc5 and below 280ff19853440d59e031cd8fe161e81305721262 is affected.
- Version 099b765139929efdcf232f8870804accf8c4cdc5 and below 37f61b71cbc0caefc01022a19ee56fc2510e2e6e is affected.
- Version 2.6.30 is affected.
- Before 2.6.30 is unaffected.
- Version 6.6.158, <= 6.6.* is unaffected.
- Version 6.12.111, <= 6.12.* is unaffected.
- Version 6.18.53, <= 6.18.* is unaffected.
- Version 7.2.7, <= 7.2.* is unaffected.
- Version 7.3-rc2, <= * is unaffected.