CVE-2026-98400 affecting package kernel 6.6.157.1-1

{
  "id": "6a5bdb0cf85f6301f4669c79ba7a81de177f3199c1f4b5ab4a8bd97eddc034dc",
  "url": "https://osv.dev/vulnerability/AZL-108167",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2026-98400 affecting package kernel 6.6.157.1-1",
    "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.",
    "evidence": "osv:AZL-108167",
    "products": [
      {
        "name": {
          "value": "kernel",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "AZL-108167",
      "aliases": [
        "AZL-108167"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "6.6.157.1-1"
                }
              ]
            }
          ],
          "package": {
            "name": "kernel",
            "purl": "pkg:rpm/azure-linux/kernel",
            "ecosystem": "Azure Linux:3"
          },
          "database_specific": {
            "source": "https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-108167.json"
          }
        }
      ],
      "modified": "2026-10-15T14:17:16.996489749Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-98400"
      ],
      "references": [
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98400"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-98400",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 332589,
  "published_at": "2026-10-14T14:17:51+00:00"
}