HighCVE-2026-53168

    Linux Kernel: security vulnerability (CVE-2026-53168)

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

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: fuse: reject fuse_notify() pagecache ops on directories The operations FUSE_NOTIFY_STORE and FUSE_NOTIFY_RETRIEVE allow the FUSE daemon to actively write/read pagecache contents. For directories with FOPEN_CACHE_DIR, the pagecache is used as kernel-internal cache storage, and userspace is not supposed to have direct access to this cache - in particular, fuse_parse_cache() will hit WARN_ON() if the cache contains bogus data.

    Update Linux Kernel to version 5.10.259, Linux Kernel to version 5.15.210, Linux Kernel to version 6.1.176.

    Affected
    • Linux Kernel lt 4.20..5.10.259
    • Linux Kernel lt 5.11..5.15.210
    • Linux Kernel lt 5.16..6.1.176
    • Linux Kernel lt 6.2..6.6.143
    • Linux Kernel lt 6.7..6.12.94
    • Linux Kernel lt 6.13..6.18.36
    • Linux Kernel lt 6.19..7.0.13
    Fixed in
    • Linux Kernel 5.10.259
    • Linux Kernel 5.15.210
    • Linux Kernel 6.1.176
    • Linux Kernel 6.6.143
    • Linux Kernel 6.12.94
    • Linux Kernel 6.18.36
    • Linux Kernel 7.0.13
    • Linux Kernel 7.1

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

    Metrics

    7.0

    Priority

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

    Source: Vendor (CNA), CVSS v3

    5.5

    CVSS v3

    Severity Medium on the scale from 0 to 10.

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

    0.1 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 2.2

    Show all metrics
    Severity
    High
    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
    47.06 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
    7.0 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
    0.1 %
    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
    2.2
    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
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    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: fuse: reject fuse_notify() pagecache ops on directories The operations FUSE_NOTIFY_STORE and FUSE_NOTIFY_RETRIEVE allow the FUSE daemon to actively write/read pagecache contents. For directories with FOPEN_CACHE_DIR, the pagecache is used as kernel-internal cache storage, and userspace is not supposed to have direct access to this cache - in particular, fuse_parse_cache() will hit WARN_ON() if the cache contains bogus data. Reject FUSE_NOTIFY_STORE and FUSE_NOTIFY_RETRIEVE on anything other than regular files with -EINVAL.

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

    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
    • 4.20 – < 5.10.259
    • 6.7 – < 6.12.94
    • 6.13 – < 6.18.36
    • 5.11 – < 5.15.210
    • —
    • 5.16 – < 6.1.176
    • 6.19 – < 7.0.13
    • 6.2 – < 6.6.143
    • 5.10.259
    • 6.12.94
    • 6.18.36
    • 5.15.210
    • 7.1
    • 6.1.176
    • 7.0.13
    • 6.6.143
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxdebianlinux-6.1bullseye
    Linuxubuntulinux-oracle-7.0noble
    Linuxlinuxlinux_kernel7.1
    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 modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/12df4cfa738aefff21756728e91056d7defb0fe6
      Referenceadded
      —
      https://git.kernel.org/stable/c/15487f98863dc7156ed43c5be26d478beb82ba35
      Referenceadded
      —
      https://git.kernel.org/stable/c/99c317d7f8b7bbf3de16d20a01f363e390114cea
      Referenceadded
      —
      https://git.kernel.org/stable/c/9c954499d43aefac01c5dfb57a82b13d2dcf4b94
      Referenceadded
      —
      https://git.kernel.org/stable/c/9dbf1b2fadfc6c40805631d8a8276d1639fc9ab6
      Referenceadded
      —
      https://git.kernel.org/stable/c/bd23fa0c16c5c86e5b7713224ffbb87d9db81cca
      Referenceadded
      —
      https://git.kernel.org/stable/c/dd92773d4d9cea010474eb08a5133c14ff6ab53a
      Referenceadded
      —
      https://git.kernel.org/stable/c/e692f0cb86204dcdb9dddc0b355407eda6394a67
      Referenceremoved
      https://git.kernel.org/stable/c/12df4cfa738aefff21756728e91056d7defb0fe6
      —
      Referenceremoved
      https://git.kernel.org/stable/c/15487f98863dc7156ed43c5be26d478beb82ba35
      —
      Referenceremoved
      https://git.kernel.org/stable/c/99c317d7f8b7bbf3de16d20a01f363e390114cea
      —
      Referenceremoved
      https://git.kernel.org/stable/c/9c954499d43aefac01c5dfb57a82b13d2dcf4b94
      —
      Referenceremoved
      https://git.kernel.org/stable/c/9dbf1b2fadfc6c40805631d8a8276d1639fc9ab6
      —
      Referenceremoved
      https://git.kernel.org/stable/c/bd23fa0c16c5c86e5b7713224ffbb87d9db81cca
      —
      Referenceremoved
      https://git.kernel.org/stable/c/dd92773d4d9cea010474eb08a5133c14ff6ab53a
      —
      Referenceremoved
      https://git.kernel.org/stable/c/e692f0cb86204dcdb9dddc0b355407eda6394a67
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/12df4cfa738aefff21756728e91056d7defb0fe6 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/15487f98863dc7156ed43c5be26d478beb82ba35 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/99c317d7f8b7bbf3de16d20a01f363e390114cea Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/9c954499d43aefac01c5dfb57a82b13d2dcf4b94 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/9dbf1b2fadfc6c40805631d8a8276d1639fc9ab6 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/bd23fa0c16c5c86e5b7713224ffbb87d9db81cca Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/dd92773d4d9cea010474eb08a5133c14ff6ab53a Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/e692f0cb86204dcdb9dddc0b355407eda6394a67 Types: Patch
      —

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

    2. 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/2026/53xxx/CVE-2026-53168.json">CVE-2026-53168</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

    3. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (5.16 – before 6.1.176; 6.2 – before 6.6.143; 5.11 – before 5.15.210; 6.13 – before 6.18.36; 6.7 – before 6.12.94; 6.19 – before 7.0.13; 4.20 – before 5.10.259; 6 individual versions)

      CVSS V3.1: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

      Show 11 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      CVSSadded
      —
      AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
      Weakness type (CWE)added
      —
      NVD-CWE-noinfo
      Product configurationadded
      —
      OR *cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.176 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.143 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.210 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.36 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.94 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.13 *cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.20 up to (excluding) 5.10.259
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/12df4cfa738aefff21756728e91056d7defb0fe6 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/15487f98863dc7156ed43c5be26d478beb82ba35 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/99c317d7f8b7bbf3de16d20a01f363e390114cea Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/9c954499d43aefac01c5dfb57a82b13d2dcf4b94 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/9dbf1b2fadfc6c40805631d8a8276d1639fc9ab6 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/bd23fa0c16c5c86e5b7713224ffbb87d9db81cca Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/dd92773d4d9cea010474eb08a5133c14ff6ab53a Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/e692f0cb86204dcdb9dddc0b355407eda6394a67 Types: Patch

      Source identifier: nvd@nist.gov

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