CVE Catalog

CVE-2025-38733

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.15%

5th percentile - higher than 5% of all known CVEs

Summary

In the Linux kernel for the s390 architecture, a vulnerability was found where the identity mapping always includes the lowcore area, even when the relocate_lowcore option is set. This causes double mapping of lowcore and allows NULL pointer accesses to succeed instead of causing an exception.

Risk Assessment

An attacker could exploit this vulnerability to gain access to kernel memory via NULL pointer operations, potentially leading to privilege escalation or data confidentiality breaches.

Recommendation

Update the Linux kernel to a version containing the fix that prevents mapping the first two pages of physical memory in the identity mapping.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS