{"id":"CVE-2026-98400","title":"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","summary":"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 …","severity":"none","published":"2026-10-14","updated":"2026-10-14","sourceUpdated":"2026-10-14T14:17:51.010","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98400","references":[{"url":"https://git.kernel.org/stable/c/030e88812435fc5d6aa42eee41fa77b5ea620327","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/50f9c40768e84f30d374235b3ee3850a94d9ac29","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7f918871112e8e7c581e99eb8e545af4e59c8367","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/92d0829eae257544b6b0faccb6e7079c45e22d48","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b6bf82bc5e00afaf836f8bb9a676bffc182a6bbd","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"ingestedAt":"2026-10-14T15:36:13.980Z","slug":"CVE-2026-98400","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}