HighCVE-2026-64379

    Linux Kernel: Improper Input Validation (CVE-2026-64379)

    Published Last modified Sources: Ubuntu, Red Hat, Debian LTS, BSI, CVE.org, Msrc Update Guide

    Share

    What is affected, what to do

    A flaw was found in the Linux kernel's Server Message Block (SMB) client. When processing server-provided file mode information, the system incorrectly applies these modes without proper security masking.

    Update Linux Kernel to version 5.10.261, Linux Kernel to version 5.15.212, Linux Kernel to version 6.1.178.

    Affected
    • Linux Kernel lt 5.4..5.10.261
    • Linux Kernel lt 5.11..5.15.212
    • Linux Kernel lt 5.16..6.1.178
    • Linux Kernel lt 6.2..6.6.145
    • Linux Kernel lt 6.7..6.12.96
    • Linux Kernel lt 6.13..6.18.39
    • Linux Kernel lt 6.19..7.1.4
    Fixed in
    • Linux Kernel 5.10.261
    • Linux Kernel 5.15.212
    • Linux Kernel 6.1.178
    • Linux Kernel 6.6.145
    • Linux Kernel 6.12.96
    • Linux Kernel 6.18.39
    • Linux Kernel 7.1.4
    • Linux Kernel 7.2

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

    Metrics

    7.1

    Priority

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

    Source: NVD, CVSS v3

    7.1

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: Ubuntu, Red Hat, Debian LTS, BSI, CVE.org, Msrc Update Guide

    0.3 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 23.8

    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
    61.16 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
    7.1 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
    7.1
    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
    0.3 %
    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
    23.8
    Elevated — this CVE ranks above at least 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
    CISA assessment (SSVC)
    Exploitation: none known · not automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 16 October 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-20

    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

    A flaw was found in the Linux kernel's Server Message Block (SMB) client. When processing server-provided file mode information, the system incorrectly applies these modes without proper security masking. This can result in unintended file permissions, potentially allowing unauthorized access to files or directories.

    Source: Ubuntu Security Notices, redhat_csaf, Debian LTS Advisories, BSI WID Portal, BSI CSAF, cvelistv5, NVD (NIST), Microsoft Security Update Guide

    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
    • 5.11 – < 5.15.212
    • 5.4 – < 5.10.261
    • 6.19 – < 7.1.4
    • 6.2 – < 6.6.145
    • 6.7 – < 6.12.96
    • —
    • 6.13 – < 6.18.39
    • 5.16 – < 6.1.178
    • 5.15.212
    • 5.10.261
    • 7.1.4
    • 6.6.145
    • 6.12.96
    • 7.2
    • 6.18.39
    • 6.1.178
    IBMQRadar SIEM
    • < 7.6.0.3
    • <7.5.0 UP16 IF01
    • 7.6.0.3
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxubuntulinuxnoble
    Linuxdebianlinux-6.1bullseye
    Linuxdebianlinux-6.12bookworm
    Linuxubuntulinux-awsnoble
    Linuxubuntulinux-aws-fipsnoble
    Linuxubuntulinux-azurenoble
    Linuxubuntulinux-azure-fdenoble
    Linuxubuntulinux-azure-fipsnoble
    Linuxubuntulinux-fipsnoble
    Linuxubuntulinux-gcpnoble
    Linuxubuntulinux-gcp-fipsnoble
    Linuxubuntulinux-gkenoble
    Linuxubuntulinux-gkeopnoble
    Linuxubuntulinux-ibmnoble
    Linuxubuntulinux-lowlatencynoble
    Linuxubuntulinux-nvidiajammy
    Linuxubuntulinux-nvidia-tegrajammy
    Linuxubuntulinux-nvidia-tegra-5.15focal
    Linuxubuntulinux-nvidia-tegra-igxjammy
    Linuxubuntulinux-oraclenoble
    Linuxubuntulinux-realtimenoble
    Linuxlinuxlinux_kernel7.2

    Weakness classes (CWE)

    • CWE-20Improper Input Validation

      Class

      The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

      Entry at MITRE CWE-20

    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 modifiedCISA ADP

      Weakness type: CWE-20

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-20

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. Record modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/08c600b7e1818539ba5efee4cdb06215c245ca78
      Referenceadded
      —
      https://git.kernel.org/stable/c/5f6f2241034f189c69d4d0b5f8fe24a0c25b0c14
      Referenceadded
      —
      https://git.kernel.org/stable/c/b84e002e0df26bbc6cbd3ca01b8212601fe0ae7d
      Referenceadded
      —
      https://git.kernel.org/stable/c/c6c484a7d5bff6b929a86d7ed5130f29834c6a0d
      Referenceadded
      —
      https://git.kernel.org/stable/c/e3d9c7160d483fc8f9e225aafad8ecbbc43f3151
      Referenceadded
      —
      https://git.kernel.org/stable/c/ee2216dbdf0c677e89bb43e03247dba590ed00ef
      Referenceadded
      —
      https://git.kernel.org/stable/c/f511807feee7cb29b61bdfa86472c7e9e2e5df94
      Referenceadded
      —
      https://git.kernel.org/stable/c/f80add1bfb3425100a325b14f19648e75669a954
      Referenceremoved
      https://git.kernel.org/stable/c/08c600b7e1818539ba5efee4cdb06215c245ca78
      —
      Referenceremoved
      https://git.kernel.org/stable/c/5f6f2241034f189c69d4d0b5f8fe24a0c25b0c14
      —
      Referenceremoved
      https://git.kernel.org/stable/c/b84e002e0df26bbc6cbd3ca01b8212601fe0ae7d
      —
      Referenceremoved
      https://git.kernel.org/stable/c/c6c484a7d5bff6b929a86d7ed5130f29834c6a0d
      —
      Referenceremoved
      https://git.kernel.org/stable/c/e3d9c7160d483fc8f9e225aafad8ecbbc43f3151
      —
      Referenceremoved
      https://git.kernel.org/stable/c/ee2216dbdf0c677e89bb43e03247dba590ed00ef
      —
      Referenceremoved
      https://git.kernel.org/stable/c/f511807feee7cb29b61bdfa86472c7e9e2e5df94
      —
      Referenceremoved
      https://git.kernel.org/stable/c/f80add1bfb3425100a325b14f19648e75669a954
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/08c600b7e1818539ba5efee4cdb06215c245ca78 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/5f6f2241034f189c69d4d0b5f8fe24a0c25b0c14 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/b84e002e0df26bbc6cbd3ca01b8212601fe0ae7d Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/c6c484a7d5bff6b929a86d7ed5130f29834c6a0d Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/e3d9c7160d483fc8f9e225aafad8ecbbc43f3151 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/ee2216dbdf0c677e89bb43e03247dba590ed00ef Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/f511807feee7cb29b61bdfa86472c7e9e2e5df94 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/f80add1bfb3425100a325b14f19648e75669a954 Types: Patch
      —

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

    3. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-64379","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:39:44.157534Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    4. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (5.11 – before 5.15.212; 5.16 – before 6.1.178; 6.2 – before 6.6.145; 6.7 – before 6.12.96; 6.13 – before 6.18.39; 6.19 – before 7.1.4; 5.4 – before 5.10.261; 2 individual versions)
      Show 10 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      NVD-CWE-noinfo
      Product configurationadded
      —
      OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.212 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.178 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.145 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.96 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.39 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.1.4 *cpe:2.3:o:linux:linux_kernel:7.2:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.2:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.4 up to (excluding) 5.10.261
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/08c600b7e1818539ba5efee4cdb06215c245ca78 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/5f6f2241034f189c69d4d0b5f8fe24a0c25b0c14 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/b84e002e0df26bbc6cbd3ca01b8212601fe0ae7d Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/c6c484a7d5bff6b929a86d7ed5130f29834c6a0d Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/e3d9c7160d483fc8f9e225aafad8ecbbc43f3151 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/ee2216dbdf0c677e89bb43e03247dba590ed00ef Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/f511807feee7cb29b61bdfa86472c7e9e2e5df94 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/f80add1bfb3425100a325b14f19648e75669a954 Types: Patch

      Source identifier: nvd@nist.gov

    5. Record modifiedLinux

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      Linux, Linux
      Linux, Linux

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

    Show one older change

    1. ReceivedLinux

      Description added or changed

      Show 10 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Linux, Linux
      Descriptionadded
      —
      In the Linux kernel, the following vulnerability has been resolved: smb: client: mask server-provided mode to 07777 in modefromsid When modefromsid is active, parse_dacl() applies the server-provided sub_auth[2] value from the NFS mode SID to cf_mode without masking to 07777. Apply the correct masking, same as in the read path.
      Referenceadded
      —
      https://git.kernel.org/stable/c/08c600b7e1818539ba5efee4cdb06215c245ca78
      Referenceadded
      —
      https://git.kernel.org/stable/c/5f6f2241034f189c69d4d0b5f8fe24a0c25b0c14
      Referenceadded
      —
      https://git.kernel.org/stable/c/b84e002e0df26bbc6cbd3ca01b8212601fe0ae7d
      Referenceadded
      —
      https://git.kernel.org/stable/c/c6c484a7d5bff6b929a86d7ed5130f29834c6a0d
      Referenceadded
      —
      https://git.kernel.org/stable/c/e3d9c7160d483fc8f9e225aafad8ecbbc43f3151
      Referenceadded
      —
      https://git.kernel.org/stable/c/ee2216dbdf0c677e89bb43e03247dba590ed00ef
      Referenceadded
      —
      https://git.kernel.org/stable/c/f511807feee7cb29b61bdfa86472c7e9e2e5df94
      Referenceadded
      —
      https://git.kernel.org/stable/c/f80add1bfb3425100a325b14f19648e75669a954

      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-2026-64379
    <a href="https://intel.neosec.eu/en/cve/CVE-2026-64379"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-64379.svg?lang=en" alt="CVE-2026-64379 – NEOSEC Intel" height="20"></a>