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Findings

CVE-2025-38733

In the Linux kernel, the following vulnerability has been resolved: s390/mm: Do not map lowcore with identity mapping Since the identity mapping is pinned to address z…

Published Sep 5, 2025 · updated Oct 15, 2026 · linux linux kernel

In the Linux kernel, the following vulnerability has been resolved: s390/mm: Do not map lowcore with identity mapping Since the identity mapping is pinned to address zero the lowcore is always also mapped to address zero, this happens regardless of the relocate_lowcore command line option. If the option is specified the lowcore is mapped twice, instead of only once. This means that NULL pointer accesses will succeed instead of causing an exception (low address protection still applies, but covers only parts). To fix this never map the first two pages of physical memory with the identity mapping.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 5, 2025 · NIST NVD

    Detected

    In the Linux kernel, the following vulnerability has been resolved: s390/mm: Do not map lowcore with identity mapping Since the identity mapping is pinned to address zero the lowcore is always also mapped to address zero, this happens regardless of the relocate_lowcore command line option. If the option is specified the lowcore is mapped twice, instead of only once. This means that NULL pointer ac

  2. Oct 15, 2026 · NIST NVD

    Updated

    In the Linux kernel, the following vulnerability has been resolved: s390/mm: Do not map lowcore with identity mapping Since the identity mapping is pinned to address zero the lowcore is always also mapped to address zero, this happens regardless of the relocate_lowcore command line option. If the option is specified the lowcore is mapped twice, instead of only once. This means that NULL pointer ac

Affected

  • cpe linux/linux kernelversion unspecified
  • cpe linux/linux kernel6.11
  • cpe linux/linux kernel6.17

Sources

  • CVE.orgVulnerability recordCVE-2025-38733

    Official CVE identifier

    cve.org
  • NIST NVDVulnerability recordCVE-2025-38733

    In the Linux kernel, the following vulnerability has been resolved: s390/mm: Do not map lowcore with identity mapping Since the identity mapping is pinned to address zero the lowcore is always also mapped to address zero, this happens regardless of the relocate_lowcore command

    nvd.nist.gov

References

CVE-2025-38733 · ZeroDay Findings