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.
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.
Metrics
Affected Vendors & Products
References
History
Fri, 05 Sep 2025 17:30:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Description | 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. | |
Title | s390/mm: Do not map lowcore with identity mapping | |
References |
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Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-09-05T17:20:33.075Z
Reserved: 2025-04-16T04:51:24.033Z
Link: CVE-2025-38733

No data.

Status : Received
Published: 2025-09-05T18:15:42.550
Modified: 2025-09-05T18:15:42.550
Link: CVE-2025-38733

No data.

No data.