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CVE-2026-98399 Linux CVE debrief

A Linux kernel vulnerability was resolved, addressing a NULL dereference issue in the s390/ipl dump_reipl function when no re-IPL parameter block is available. This fix prevents potential crashes by explicitly storing a zero IPL parameter block address and checksum when no re-IPL parameter block is available, ensuring the stand-alone dumper completes the dump and halts, while valid re-IPL parameter blocks continue to be handled as before. Linux administrators should verify and apply patches for affected Linux kernel versions to prevent potential issues. The fix involves updating the IPL parameter block address and checksum in lowcore to prevent NULL dereferences.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-14
Original CVE updated
2026-10-14
Advisory published
2026-10-14
Advisory updated
2026-10-14

Who should care

Linux administrators and users should verify and apply patches for affected Linux kernel versions to prevent potential issues. The vulnerability affects Linux kernel versions with the s390/ipl: Fix NULL deref in dump_reipl without re-IPL parm block vulnerability. Operators, platform administrators, and security teams should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Why it matters

Linux administrators and users should verify and apply patches for affected Linux kernel versions to prevent potential issues.

  • Verify Linux kernel versions for s390/ipl: Fix NULL deref in dump_reipl without re-IPL parm block vulnerability
  • Apply patches for affected Linux kernel versions to prevent potential crashes

Technical summary

The Linux kernel had a vulnerability in the s390/ipl dump_reipl function, which could lead to a NULL dereference when no re-IPL parameter block was available. A fix has been applied to address this issue by explicitly storing a zero IPL parameter block address and checksum when no re-IPL parameter block is available. This fix prevents potential crashes and ensures the stand-alone dumper completes the dump and halts, while valid re-IPL parameter blocks continue to be handled as before. Linux administrators and users should verify and apply patches for affected Linux kernel versions to prevent potential issues.

Defensive priority

Verify and apply patches for Linux kernel versions with the s390/ipl: Fix NULL deref in dump_reipl without re-IPL parm block vulnerability.

Recommended defensive actions

  • Verify Linux kernel versions for s390/ipl: Fix NULL deref in dump_reipl without re-IPL parm block vulnerability
  • Apply patches for affected Linux kernel versions
  • Monitor Linux kernel updates for additional security fixes
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the Linux kernel vulnerability and its fix. The vulnerability was introduced in the s390/ipl dump_reipl function, which could lead to a NULL dereference when no re-IPL parameter block was available. The fix has been applied to address this issue. Linux administrators and users should verify and apply patches for affected Linux kernel versions to prevent potential issues. The fix does not change the behavior of the stand-alone dumper, which completes the dump and halts, while valid re-

Sources and references

Verified primary and authoritative sources

  • CVE-2026-98399 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-98399

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-98399 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-98399

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • s390/ipl: Fix NULL deref in dump_reipl without re-IPL parm block

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/98xxx/CVE-2026-98399.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/41647864e62b28388ecccc23a82f0e0a091f4ef2

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/aed56fa3108b7095e6a048e134981506c056a6cb

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/8d7988e8116c3d29d9e02ca9d37ee84577643f2d

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/280ff19853440d59e031cd8fe161e81305721262

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/37f61b71cbc0caefc01022a19ee56fc2510e2e6e

    Supplemental source

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.