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CVE-2026-98400

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CVE-2026-98400 is a vulnerability of currently unknown severity. 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.

Description

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.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 3b9678472bab86ae654cf2c18d5dd551558045be, < 030e88812435fc5d6aa42eee41fa77b5ea620327; >= 3b9678472bab86ae654cf2c18d5dd551558045be, < 92d0829eae257544b6b0faccb6e7079c45e22d48; >= 3b9678472bab86ae654cf2c18d5dd551558045be, < 50f9c40768e84f30d374235b3ee3850a94d9ac29; >= 3b9678472bab86ae654cf2c18d5dd551558045be, < b6bf82bc5e00afaf836f8bb9a676bffc182a6bbd; >= 3b9678472bab86ae654cf2c18d5dd551558045be, < 7f918871112e8e7c581e99eb8e545af4e59c8367
LinuxLinux4.17

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is 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. 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.
How severe is CVE-2026-98400?
Severity scoring for CVE-2026-98400 is pending analysis.
How do I fix CVE-2026-98400?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST