CVE-2025-38733
MEDIUM EPSS 4.0%
Published Sep 5, 20259mo ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Published Sep 5, 2025 9mo ago
Last Modified Jun 17, 2026 1w ago
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.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High
Threat Intelligence
EPSS Exploit Probability
4.0% percentile
Exploit & Patch Status
No Known Exploit
Patch Available
Weaknesses 1
CWE-476 NULL Pointer Dereference Memory Safety
Affected Products 9
References 3
- git.kernel.org https://git.kernel.org/stable/c/1d7864acd497cb468a998d44631f84896f885e85
- git.kernel.org https://git.kernel.org/stable/c/30bf5728bb217a6d1ba73f44094c9b9c6bc9a567
- git.kernel.org https://git.kernel.org/stable/c/93f616ff870a1fb7e84d472cad0af651b18f9f87
Remediation
- git.kernel.org https://git.kernel.org/stable/c/1d7864acd497cb468a998d44631f84896f885e85
- git.kernel.org https://git.kernel.org/stable/c/30bf5728bb217a6d1ba73f44094c9b9c6bc9a567
- git.kernel.org https://git.kernel.org/stable/c/93f616ff870a1fb7e84d472cad0af651b18f9f87