CVE-2026-98399
s390/ipl: Fix NULL deref in dump_reipl without re-IPL parm block
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.
INFO
Published Date :
Oct. 14, 2026, 2:17 p.m.
Last Modified :
Oct. 14, 2026, 2:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to the resolved version.
- Ensure the stand-alone dumper handles null pointers correctly.
- Verify IPL parameter block initialization.
- Restart the system after the update.
References to Advisories, Solutions, and Tools
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CWE - Common Weakness Enumeration
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associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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approaches employed by adversaries to exploit the CVE-2026-98399
weaknesses.
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 14, 2026
Action Type Old Value New Value Added 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. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/98xxx/CVE-2026-98399.json">CVE-2026-98399</a> Added Reference https://git.kernel.org/stable/c/280ff19853440d59e031cd8fe161e81305721262 Added Reference https://git.kernel.org/stable/c/37f61b71cbc0caefc01022a19ee56fc2510e2e6e Added Reference https://git.kernel.org/stable/c/41647864e62b28388ecccc23a82f0e0a091f4ef2 Added Reference https://git.kernel.org/stable/c/8d7988e8116c3d29d9e02ca9d37ee84577643f2d Added Reference https://git.kernel.org/stable/c/aed56fa3108b7095e6a048e134981506c056a6cb