MediumCVE-2025-23131

    Linux Kernel: NULL Pointer Dereference (CVE-2025-23131)

    Published Last modified Sources: Siemens ProductCERT, Debian, SUSE, Ubuntu, Debian LTS, BSI, CVE.org, Msrc Update Guide, EUVD

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: dlm: prevent NPD when writing a positive value to event_done do_uevent returns the value written to event_done. In case it is a positive value, new_lockspace would undo all the work, and lockspace would not be set. __dlm_new_lockspace, however, would treat that positive value as a success due to commit 8511a2728ab8 ("dlm: fix use count with multiple joins").

    Update Linux Kernel to version 5.10.260, Linux Kernel to version 5.15.211, Linux Kernel to version 6.1.177.

    Affected
    • Linux Kernel lt 2.6.31..5.10.260
    • Linux Kernel lt 5.11..5.15.211
    • Linux Kernel lt 5.16..6.1.177
    • Linux Kernel lt 6.2..6.6.144
    • Linux Kernel lt 6.7..6.12.95
    • Linux Kernel lt 6.13..6.14.2
    Fixed in
    • Linux Kernel 5.10.260
    • Linux Kernel 5.15.211
    • Linux Kernel 6.1.177
    • Linux Kernel 6.6.144
    • Linux Kernel 6.12.95
    • Linux Kernel 6.14.2
    • Linux Kernel 6.15

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    5.5

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    5.5

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: Siemens ProductCERT, Debian, SUSE, Ubuntu, Debian LTS, BSI, CVE.org, Msrc Update Guide, EUVD

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 8.8

    Show all metrics
    Severity
    Medium
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    36.73 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    5.5 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    5.5
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.2 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    8.8
    Low — this CVE sits in the lower 10% of all CVEs scored today.
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    In the Linux kernel, the following vulnerability has been resolved: dlm: prevent NPD when writing a positive value to event_done do_uevent returns the value written to event_done. In case it is a positive value, new_lockspace would undo all the work, and lockspace would not be set. __dlm_new_lockspace, however, would treat that positive value as a success due to commit 8511a2728ab8 ("dlm: fix use count with multiple joins"). Down the line, device_create_lockspace would pass that NULL lockspace to dlm_find_lockspace_local, leading to a NULL pointer dereference. Treating such positive values as successes prevents the problem. Given this has been broken for so long, this is unlikely to break userspace expectations.

    Source: siemens_advisory, Debian Security Advisories, suse_csaf, Ubuntu Security Notices, Debian LTS Advisories, BSI WID Portal, BSI CSAF, cvelistv5, NVD (NIST), Microsoft Security Update Guide, CVE.org (MITRE), ENISA EUVD

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    LinuxLinux
    • —
    • 5.16 – < 6.1.177
    • 6.13 – < 6.14.2
    • 5.11 – < 5.15.211
    • 2.6.31 – < 5.10.260
    • 6.7 – < 6.12.95
    • 6.2 – < 6.6.144
    • 6.15
    • 6.1.177
    • 6.14.2
    • 5.15.211
    • 5.10.260
    • 6.12.95
    • 6.6.144
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxdebianlinuxtrixie
    Linuxdebianlinux-6.1bullseye
    Linuxubuntulinux-gcp-5.15focal
    Linuxlinuxlinux_kernel—

    References & sources

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedSiemens ADP

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2025/23xxx/CVE-2025-23131.json">CVE-2025-23131</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

      Source identifier: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

    2. Record modifiedLinux

      Show 16 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/10b7a59814765d18d43555c9cef4eb3048b7e8a3
      Referenceadded
      —
      https://git.kernel.org/stable/c/7109d69bec6edce546dc870e66bd2b668a3d5549
      Referenceadded
      —
      https://git.kernel.org/stable/c/8e2bad543eca5c25cd02cbc63d72557934d45f13
      Referenceadded
      —
      https://git.kernel.org/stable/c/a1c41aebb184d9228a440dcb6761224e65b0e49a
      Referenceadded
      —
      https://git.kernel.org/stable/c/b73c4ad4d387fe5bc988145bd9f1bc0de76afd5c
      Referenceadded
      —
      https://git.kernel.org/stable/c/c7837e2c96559663c33f43da403d9cf3cf77cfa7
      Referenceadded
      —
      https://git.kernel.org/stable/c/ee28d99d789b077565cbe0377374d1e826c64d93
      Referenceremoved
      https://git.kernel.org/stable/c/10b7a59814765d18d43555c9cef4eb3048b7e8a3
      —
      Referenceremoved
      https://git.kernel.org/stable/c/7109d69bec6edce546dc870e66bd2b668a3d5549
      —
      Referenceremoved
      https://git.kernel.org/stable/c/8e2bad543eca5c25cd02cbc63d72557934d45f13
      —
      Referenceremoved
      https://git.kernel.org/stable/c/a1c41aebb184d9228a440dcb6761224e65b0e49a
      —
      Referenceremoved
      https://git.kernel.org/stable/c/b73c4ad4d387fe5bc988145bd9f1bc0de76afd5c
      —
      Referenceremoved
      https://git.kernel.org/stable/c/c7837e2c96559663c33f43da403d9cf3cf77cfa7
      —
      Referenceremoved
      https://git.kernel.org/stable/c/ee28d99d789b077565cbe0377374d1e826c64d93
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/8e2bad543eca5c25cd02cbc63d72557934d45f13 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/b73c4ad4d387fe5bc988145bd9f1bc0de76afd5c Types: Patch
      —

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    3. Record modifiedLinux

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/10b7a59814765d18d43555c9cef4eb3048b7e8a3
      Referenceadded
      —
      https://git.kernel.org/stable/c/7109d69bec6edce546dc870e66bd2b668a3d5549
      Referenceadded
      —
      https://git.kernel.org/stable/c/a1c41aebb184d9228a440dcb6761224e65b0e49a
      Referenceadded
      —
      https://git.kernel.org/stable/c/c7837e2c96559663c33f43da403d9cf3cf77cfa7
      Referenceadded
      —
      https://git.kernel.org/stable/c/ee28d99d789b077565cbe0377374d1e826c64d93
      Affected versions (publisher)changed
      Linux, Linux
      Linux, Linux

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Embed badge

    Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

    Badge preview for CVE-2025-23131
    <a href="https://intel.neosec.eu/en/cve/CVE-2025-23131"><img src="https://intel.neosec.eu/badge/cve/CVE-2025-23131.svg?lang=en" alt="CVE-2025-23131 – NEOSEC Intel" height="20"></a>