NULL pointer dereference in Linux

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 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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.002 (5.2th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 5th percentile — 5.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-38733: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

  • Linux — versions 6.10.11, 0b99d0e17d6a73a0526f92bc6b54b2b95e67a31d, 6.17
  • Linux Kernel — versions 6.11, 6.17

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-38733?
CVE-2025-38733 is a high-severity vulnerability in Linux, classified under NULL Pointer Dereference. CVSS score: 7.8/10. Published 2025-09-05.
How severe is CVE-2025-38733?
High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2025-38733 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.