CVE-2025-38733

Local privilege escalation via identity-mapped lowcore

Published Sep 5, 2025 · Updated Aug 5, 2026

Incorrect lowcore mapping in affected Linux kernel releases on s390 allows local users to read or corrupt kernel memory via NULL access. The s390 boot-time page-table setup in arch/s390/boot/vmem.c identity-maps the first two physical pages, placing lowcore at address zero even when relocation is enabled. An unprivileged local user who can invoke a kernel path containing a NULL dereference can gain full kernel control or panic the host.

CVSS severity7.8
High
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect lowcore mapping in affected Linux kernel releases on s390 allows local users to read or corrupt kernel memory via NULL access. The s390 boot-time page-table setup in arch/s390/boot/vmem.c identity-maps the first two physical pages, placing lowcore at address zero even when relocation is enabled. An unprivileged local user who can invoke a kernel path containing a NULL dereference can gain full kernel control or panic the host.

The record

CVE
CVE-2025-38733
Published
Sep 5, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0b99d0e17d6a73a0526f92bc6b54b2b95e67a31d
  2. Affected versionversion=32db401965f165f7c44447d0508097f070c8f576 <1d7864acd497cb468a998d44631f84896f885e85
  3. Affected versionversion=32db401965f165f7c44447d0508097f070c8f576 <30bf5728bb217a6d1ba73f44094c9b9c6bc9a567
  4. Affected versionversion=32db401965f165f7c44447d0508097f070c8f576 <93f616ff870a1fb7e84d472cad0af651b18f9f87
  5. Affected versionversion=6.10.11 <6.11
  6. Affected versionversion=6.11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0b99d0e17d6a73a0526f92bc6b54b2b95e67a31d; version=32db401965f165f7c44447d0508097f070c8f576 <1d7864acd497cb468a998d44631f84896f885e85; version=32db401965f165f7c44447d0508097f070c8f576 <30bf5728bb217a6d1ba73f44094c9b9c6bc9a567; version=32db401965f165f7c44447d0508097f070c8f576 <93f616ff870a1fb7e84d472cad0af651b18f9f87; version=6.10.11 <6.11; version=6.11

Published CVSS scores

7.8Linux CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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