{"id":"CVE-2026-98400","summary":"s390/ipl: Fix NULL deref in kdump without re-IPL parm block","details":"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.","modified":"2026-10-15T02:47:42.110051104Z","published":"2026-10-14T13:26:00.872Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98400.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/030e88812435fc5d6aa42eee41fa77b5ea620327"},{"type":"WEB","url":"https://git.kernel.org/stable/c/50f9c40768e84f30d374235b3ee3850a94d9ac29"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7f918871112e8e7c581e99eb8e545af4e59c8367"},{"type":"WEB","url":"https://git.kernel.org/stable/c/92d0829eae257544b6b0faccb6e7079c45e22d48"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b6bf82bc5e00afaf836f8bb9a676bffc182a6bbd"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98400.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98400"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3b9678472bab86ae654cf2c18d5dd551558045be"},{"fixed":"030e88812435fc5d6aa42eee41fa77b5ea620327"},{"fixed":"92d0829eae257544b6b0faccb6e7079c45e22d48"},{"fixed":"50f9c40768e84f30d374235b3ee3850a94d9ac29"},{"fixed":"b6bf82bc5e00afaf836f8bb9a676bffc182a6bbd"},{"fixed":"7f918871112e8e7c581e99eb8e545af4e59c8367"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98400.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.17.0"},{"fixed":"6.6.158"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.111"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98400.json"}}],"schema_version":"1.9.0"}