CVE-2026-98400 (GCVE-0-2026-98400)

Vulnerability from cvelistv5 – Published: 2026-10-14 13:26 – Updated: 2026-10-14 13:26
VLAI
Title
s390/ipl: Fix NULL deref in kdump without re-IPL parm block
Summary
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.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6666 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 3b9678472bab86ae654cf2c18d5dd551558045be , < 030e88812435fc5d6aa42eee41fa77b5ea620327 (git)
Affected: 3b9678472bab86ae654cf2c18d5dd551558045be , < 92d0829eae257544b6b0faccb6e7079c45e22d48 (git)
Affected: 3b9678472bab86ae654cf2c18d5dd551558045be , < 50f9c40768e84f30d374235b3ee3850a94d9ac29 (git)
Affected: 3b9678472bab86ae654cf2c18d5dd551558045be , < b6bf82bc5e00afaf836f8bb9a676bffc182a6bbd (git)
Affected: 3b9678472bab86ae654cf2c18d5dd551558045be , < 7f918871112e8e7c581e99eb8e545af4e59c8367 (git)
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Linux Linux Affected: 4.17
Unaffected: 0 , < 4.17 (semver)
Unaffected: 6.6.158 , ≤ 6.6.* (semver)
Unaffected: 6.12.111 , ≤ 6.12.* (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc2 , ≤ * (original_commit_for_fix)
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Show details on NVD website
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/ipl: Fix NULL deref in kdump without re-IPL parm block\n\nSome IPL types, like HMC FTP boot or QEMU direct kernel boot, might\nnot provide an IPL parameter block. In this case, reipl_type_init()\nselects IPL_TYPE_UNKNOWN, and reipl_block_actual remains NULL.\n\nkdump passes the re-IPL parameter block to the dump kernel through\nos_info. Before commit 3b9678472bab (\"s390/ipl: correct kdump reipl\nblock checksum calculation\"), the os_info entry was added only for\nIPL types which initialized reipl_block_actual. That commit moved the\nos_info update to machine_crash_shutdown(), making it unconditional. As\na result, set_os_info_reipl_block() dereferences reipl_block_actual for\nIPL_TYPE_UNKNOWN. This may happen to work by chance when address zero\ncontains readable lowcore data and the resulting empty os_info entry is\nignored by the dump kernel.\n\nSkip the os_info update when no re-IPL parameter block is available.\nKdump then collect the dump and reboot without setting re-IPL parameter\nblock."
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      "cve": "CVE-2026-98400",
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}



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