CriticalCVE-2026-46195

    Linux Kernel: security vulnerability (CVE-2026-46195)

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

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building DACL pointers parse_sec_desc(), build_sec_desc(), and the chown path in id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd before proving a DACL header fits inside the returned security descriptor. On 32-bit builds a malicious server can return dacloffset near U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip past the later pointer-based bounds checks. build_sec_desc() and id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped pointer in the chmod/chown rewrite paths.

    Update Linux Kernel to version 5.15.210, Linux Kernel to version 6.1.176, Linux Kernel to version 6.6.140.

    Affected
    • Linux Kernel lt 5.12..5.15.210
    • Linux Kernel lt 5.16..6.1.176
    • Linux Kernel lt 6.2..6.6.140
    • Linux Kernel lt 6.7..6.12.88
    • Linux Kernel lt 6.13..6.18.30
    • Linux Kernel lt 6.19..7.0.7
    Fixed in
    • Linux Kernel 5.15.210
    • Linux Kernel 6.1.176
    • Linux Kernel 6.6.140
    • Linux Kernel 6.12.88
    • Linux Kernel 6.18.30
    • Linux Kernel 7.0.7
    • Linux Kernel 7.1

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

    Metrics

    9.8

    Priority

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

    Source: Vendor (CNA), CVSS v3

    9.8

    CVSS v3

    Severity Critical on the scale from 0 to 10.

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

    0.7 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 52.2

    Show all metrics
    Severity
    Critical
    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
    88.73 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
    9.8 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
    9.8
    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
    0.7 %
    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
    52.2
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    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 · automatable · Technical impact: total
    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-190

    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: smb: client: validate dacloffset before building DACL pointers parse_sec_desc(), build_sec_desc(), and the chown path in id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd before proving a DACL header fits inside the returned security descriptor. On 32-bit builds a malicious server can return dacloffset near U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip past the later pointer-based bounds checks. build_sec_desc() and id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped pointer in the chmod/chown rewrite paths. Validate dacloffset numerically before building any DACL pointer and reuse the same helper at the three DACL entry points.

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

    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
    • 6.7 – < 6.12.88
    • 6.2 – < 6.6.140
    • 6.19 – < 7.0.7
    • 5.12 – < 5.15.210
    • —
    • 5.16 – < 6.1.176
    • 6.13 – < 6.18.30
    • 6.12.88
    • 6.6.140
    • 7.0.7
    • 5.15.210
    • 7.1
    • 6.1.176
    • 6.18.30
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinux-6.1bullseye
    Linuxlinuxlinux_kernel7.1
    Linuxlinuxlinux_kernel—

    Weakness classes (CWE)

    • CWE-190Integer Overflow or Wraparound

      Base

      The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

      Entry at MITRE CWE-190

    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-190

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-190

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

    2. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: yes

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-46195","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:20:56.572317Z"}

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

    3. Record modifiedLinux

      Show 19 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/3b1ddba19e77ee35241cd27f16dc3e8d14e08db7
      Referenceadded
      —
      https://git.kernel.org/stable/c/5de2665e913a10ad70aaeecf736b97276e83d995
      Referenceadded
      —
      https://git.kernel.org/stable/c/8bd07e417b6bda67e317920584e48cb6ee442a8a
      Referenceadded
      —
      https://git.kernel.org/stable/c/ba7f71b6161c0943dafc367565e5843d16b7d505
      Referenceadded
      —
      https://git.kernel.org/stable/c/c688f3ed73d31943334ad2139cb02ec49664322a
      Referenceadded
      —
      https://git.kernel.org/stable/c/f98b48151cc502ada59d9778f0112d21f2586ca3
      Referenceadded
      —
      https://git.kernel.org/stable/c/f9dc3be8f403c1216df73e57221f44b045e7ee0b
      Referenceremoved
      https://git.kernel.org/stable/c/3b1ddba19e77ee35241cd27f16dc3e8d14e08db7
      —
      Referenceremoved
      https://git.kernel.org/stable/c/5de2665e913a10ad70aaeecf736b97276e83d995
      —
      Referenceremoved
      https://git.kernel.org/stable/c/8bd07e417b6bda67e317920584e48cb6ee442a8a
      —
      Referenceremoved
      https://git.kernel.org/stable/c/ba7f71b6161c0943dafc367565e5843d16b7d505
      —
      Referenceremoved
      https://git.kernel.org/stable/c/c688f3ed73d31943334ad2139cb02ec49664322a
      —
      Referenceremoved
      https://git.kernel.org/stable/c/f98b48151cc502ada59d9778f0112d21f2586ca3
      —
      Referenceremoved
      https://git.kernel.org/stable/c/f9dc3be8f403c1216df73e57221f44b045e7ee0b
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/3b1ddba19e77ee35241cd27f16dc3e8d14e08db7 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/8bd07e417b6bda67e317920584e48cb6ee442a8a Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/ba7f71b6161c0943dafc367565e5843d16b7d505 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/c688f3ed73d31943334ad2139cb02ec49664322a Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/f98b48151cc502ada59d9778f0112d21f2586ca3 Types: Patch
      —

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

    4. Record modifiedRed Hat ADP

      Show 12 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:21556
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:21706
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:21745
      Referenceadded
      —
      https://access.redhat.com/security/cve/CVE-2026-46195
      Referenceadded
      —
      https://bugzilla.redhat.com/show_bug.cgi?id=2482606
      Referenceadded
      —
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46195.json
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:21556
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:21706
      —
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:21745
      —
      Referenceremoved
      https://access.redhat.com/security/cve/CVE-2026-46195
      —
      Referenceremoved
      https://bugzilla.redhat.com/show_bug.cgi?id=2482606
      —
      Referenceremoved
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46195.json
      —

      Source identifier: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

    5. 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/2026/46xxx/CVE-2026-46195.json">CVE-2026-46195</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

    Show 2 older changes

    1. Record modifiedLinux

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/5de2665e913a10ad70aaeecf736b97276e83d995
      Referenceadded
      —
      https://git.kernel.org/stable/c/f9dc3be8f403c1216df73e57221f44b045e7ee0b
      Affected versions (publisher)changed
      Linux, Linux
      Linux, Linux

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

    2. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (6.13 – before 6.18.30; 6.19 – before 7.0.7; 6.7 – before 6.12.88; 5.12 – before 6.6.140; 2 individual versions)

      Weakness type: CWE-476

      Show 7 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-476
      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:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.30 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.7 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.88 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.12 up to (excluding) 6.6.140
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/3b1ddba19e77ee35241cd27f16dc3e8d14e08db7 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/8bd07e417b6bda67e317920584e48cb6ee442a8a Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/ba7f71b6161c0943dafc367565e5843d16b7d505 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/c688f3ed73d31943334ad2139cb02ec49664322a Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/f98b48151cc502ada59d9778f0112d21f2586ca3 Types: Patch

      Source identifier: nvd@nist.gov

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