Linux Kernel up to 6.12.43/6.16.3/6.17-rc2 relocate_lowcore null pointer dereference

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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.12.43/6.16.3/6.17-rc2 and classified as critical. This impacts the function relocate_lowcore. The manipulation results in null pointer dereference. This vulnerability is cataloged as CVE-2025-38733. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.12.43/6.16.3/6.17-rc2. Affected is the function relocate_lowcore. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

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.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2025-38733 since 04/16/2025. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 261644 (Linux Distros Unpatched Vulnerability : CVE-2025-38733), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.44, 6.16.4 or 6.17-rc3 eliminates this vulnerability. Applying the patch 30bf5728bb217a6d1ba73f44094c9b9c6bc9a567/1d7864acd497cb468a998d44631f84896f885e85/93f616ff870a1fb7e84d472cad0af651b18f9f87 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (261644) and CERT Bund (WID-SEC-2025-1988). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Debian Linux
  • Google Cloud Platform
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • NetApp FAS
  • NetApp AFF
  • NetApp ActiveIQ Unified Manager
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel
  • Microsoft Azure
  • Dell Secure Connect Gateway
  • IBM QRadar SIEM
  • IBM Security Verify Access
  • Dell NetWorker

Productinfo

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Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.6
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 261644
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-38733

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.44/6.16.4/6.17-rc3
Patch: 30bf5728bb217a6d1ba73f44094c9b9c6bc9a567/1d7864acd497cb468a998d44631f84896f885e85/93f616ff870a1fb7e84d472cad0af651b18f9f87

Timelineinfo

04/16/2025 CVE reserved
09/05/2025 +142 days Advisory disclosed
09/05/2025 +0 days VulDB entry created
02/09/2026 +157 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-38733 (🔒)
GCVE (CVE): GCVE-0-2025-38733
GCVE (VulDB): GCVE-100-322914
CERT Bund: WID-SEC-2025-1988 - Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service

Entryinfo

Created: 09/05/2025 21:57
Updated: 02/09/2026 11:22
Changes: 09/05/2025 21:57 (58), 09/07/2025 02:11 (2), 09/09/2025 06:17 (8), 11/06/2025 14:34 (1), 11/25/2025 15:05 (1), 11/26/2025 15:10 (10), 11/27/2025 13:57 (1), 12/29/2025 11:03 (1), 01/05/2026 10:09 (1), 01/26/2026 11:25 (1), 02/09/2026 11:22 (1)
Complete: 🔍
Cache ID: 216::103

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