CVE-2026-98400
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.
Read full descriptionShow less
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.
CVSS
NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days
- 0.21 %
- Percentile among all scored CVEs
- 11
- Score date
- 10/21/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (1)
⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.
References
Show 5 references
- https://git.kernel.org/stable/c/030e88812435fc5d6aa42eee41fa77b5ea620327
- https://git.kernel.org/stable/c/50f9c40768e84f30d374235b3ee3850a94d9ac29
- https://git.kernel.org/stable/c/7f918871112e8e7c581e99eb8e545af4e59c8367
- https://git.kernel.org/stable/c/92d0829eae257544b6b0faccb6e7079c45e22d48
- https://git.kernel.org/stable/c/b6bf82bc5e00afaf836f8bb9a676bffc182a6bbd
Raw JSON (NVD)
Show
{
"id": "CVE-2026-98400",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3b9678472bab86ae654cf2c18d5dd551558045be",
"lessThan": "030e88812435fc5d6aa42eee41fa77b5ea620327",
"versionType": "git"
},
{
"status": "affected",
"version": "3b9678472bab86ae654cf2c18d5dd551558045be",
"lessThan": "92d0829eae257544b6b0faccb6e7079c45e22d48",
"versionType": "git"
},
{
"status": "affected",
"version": "3b9678472bab86ae654cf2c18d5dd551558045be",
"lessThan": "50f9c40768e84f30d374235b3ee3850a94d9ac29",
"versionType": "git"
},
{
"status": "affected",
"version": "3b9678472bab86ae654cf2c18d5dd551558045be",
"lessThan": "b6bf82bc5e00afaf836f8bb9a676bffc182a6bbd",
"versionType": "git"
},
{
"status": "affected",
"version": "3b9678472bab86ae654cf2c18d5dd551558045be",
"lessThan": "7f918871112e8e7c581e99eb8e545af4e59c8367",
"versionType": "git"
}
],
"programFiles": [
"arch/s390/kernel/ipl.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.17"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.17",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.53",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"arch/s390/kernel/ipl.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-14T14:17:51.010",
"references": [
{
"url": "https://git.kernel.org/stable/c/030e88812435fc5d6aa42eee41fa77b5ea620327",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/50f9c40768e84f30d374235b3ee3850a94d9ac29",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/7f918871112e8e7c581e99eb8e545af4e59c8367",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/92d0829eae257544b6b0faccb6e7079c45e22d48",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/b6bf82bc5e00afaf836f8bb9a676bffc182a6bbd",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"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."
}
],
"lastModified": "2026-10-19T10:18:44.820",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}