7.8

CVE-2025-38733: s390/mm: Do not map lowcore with identity mapping

Modified
AliasesUBUNTU-CVE-2025-38733DEBIAN-CVE-2025-38733
Published 05-09-2025Last modified 15-10-2026

Vulnerability summary

CVE-2025-38733 is a high (CVSS 7.8) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 5.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.17%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 6 · Related 5
DSA-6008-1OPENSUSE-SU-2025:20081-1SUSE-SU-2025:21074-1SUSE-SU-2025:21139-1SUSE-SU-2025:21179-1SUSE-SU-2026:20560-1

Timeline

  1. 05-09-2025
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

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 metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.17%

Chance of exploitation in the next 30 days

Percentile

6%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.17% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu95 products
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
  • linux-aws-5.13All versions (No fix recorded)
  • linux-aws-5.19All versions (No fix recorded)
Linux2 products
  • linux≥ 32db401965f165f7c44447d0508097f070c8f576, < 30bf5728bb217a6d1ba73f44094c9b9c6bc9a567 | ≥ 32db401965f165f7c44447d0508097f070c8f576, < 1d7864acd497cb468a998d44631f84896f885e85 | ≥ 32db401965f165f7c44447d0508097f070c8f576, < 93f616ff870a1fb7e84d472cad0af651b18f9f87 | 0b99d0e17d6a73a0526f92bc6b54b2b95e67a31d | ≥ 6.10.11, < 6.11 | 6.11
  • linux_kernelEOL≥ 6.10.11, < 6.11 | ≥ 6.11.1, < 6.12.44 | ≥ 6.13, < 6.16.4 | 6.11 | 6.11:rc5 | 6.11:rc6 | 6.11:rc7 | 6.17:rc1 | 6.17:rc2
Debian1 product
  • linux< 6.12.48-1 | < 6.16.5-1

3 vendors · 98 products

References

7 links