MediumCVE-2026-68097

    Linux Kernel: security vulnerability (CVE-2026-68097)

    Published Last modified Sources: Ubuntu, CVE.org, BSI, Msrc Update Guide

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate ACE size against SID sub-authorities set_ntacl_dacl() validates sid.num_subauth before copying an ACE, but does not verify that the declared ACE size contains all sub-authorities described by that field. An undersized ACE can therefore be copied and later make the POSIX ACL deduplication walk inspect data beyond the copied ACE boundary.

    Update Linux Kernel to version 6.1.189, Linux Kernel to version 6.6.148, Linux Kernel to version 6.12.101.

    Affected
    • Linux Kernel lt 5.15..6.1.189
    • Linux Kernel lt 6.2..6.6.148
    • Linux Kernel lt 6.7..6.12.101
    • Linux Kernel lt 6.13..6.18.42
    • Linux Kernel lt 6.19..7.1.6
    Fixed in
    • Linux Kernel 6.1.189
    • Linux Kernel 6.6.148
    • Linux Kernel 6.12.101
    • Linux Kernel 6.18.42
    • Linux Kernel 7.1.6
    • Linux Kernel 7.2

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

    Metrics

    6.3

    Priority

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

    Source: Vendor (CNA), CVSS v3

    6.3

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: Ubuntu, CVE.org, BSI, Msrc Update Guide

    0.4 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 37.8

    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
    66.44 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
    6.3 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
    6.3
    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
    0.4 %
    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
    37.8
    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

    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: ksmbd: validate ACE size against SID sub-authorities set_ntacl_dacl() validates sid.num_subauth before copying an ACE, but does not verify that the declared ACE size contains all sub-authorities described by that field. An undersized ACE can therefore be copied and later make the POSIX ACL deduplication walk inspect data beyond the copied ACE boundary. The existing initial bound check is also too small. It only ensures that the ACE size field is accessible before set_ntacl_dacl() reads sid.num_subauth farther into the input buffer. Require enough input for the fixed SID header before accessing num_subauth, reject ACEs smaller than that header, and skip ACEs whose declared size cannot contain the complete SID. This makes the validation consistent with the other ACE walk paths.

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

    Affected products

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

    Affected products
    VendorProductAffected versionsFixed in
    LinuxLinux
    • 6.7 – < 6.12.101
    • 6.2 – < 6.6.148
    • 6.13 – < 6.18.42
    • —
    • 5.15 – < 6.1.189
    • 6.19 – < 7.1.6
    • 6.12.101
    • 6.6.148
    • 6.18.42
    • 7.2
    • 6.1.189
    • 7.1.6

    Affected operating systems

    Affected operating systems
    FamilyVendorProductVersion
    Linuxubuntulinux-nvidia-tegranoble

    References & sources

    Reanalysis & status changes

    Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.

    1. CVE Modified416baaa9-dc9f-4396-8d5f-8c081fb06d67

      • Affected: after Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/68xxx/CVE-2026-68097.json">CVE-2026-68097</a>
      • Reference: after https://git.kernel.org/stable/c/337022d9dfac441c3b35e4455a51aa981996e02e
      • Reference: after https://git.kernel.org/stable/c/5152c6d49e3fd4e9f2e857c57527aead752f1f87
      • Reference: after https://git.kernel.org/stable/c/5a2d9fe0e87c71baa0aaa1cfc1361892fcd1ece0

    2. CVE Modified416baaa9-dc9f-4396-8d5f-8c081fb06d67

      • Affected: before Linux, Linux after Linux, Linux

    3. New CVE Received416baaa9-dc9f-4396-8d5f-8c081fb06d67

      • Affected: after Linux, Linux
      • Description: after In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate ACE size against SID sub-authorities set_ntacl_dacl() validates sid.num_subauth before copying an ACE, but does not verify that the declared ACE size contains all sub-authorities described by that field. An undersized ACE can therefore be copied and later make the POSIX ACL deduplication walk inspect data beyond the copied ACE boundary. The existing initial bound check is also too small. It only ensures that the ACE size field is accessible before set_ntacl_dacl() reads sid.num_subauth farther into the input buffer. Require enough input for the fixed SID header before accessing num_subauth, reject ACEs smaller than that header, and skip ACEs whose declared size cannot contain the complete SID. This makes the validation consistent with the other ACE walk paths.
      • Reference: after https://git.kernel.org/stable/c/337022d9dfac441c3b35e4455a51aa981996e02e
      • Reference: after https://git.kernel.org/stable/c/5152c6d49e3fd4e9f2e857c57527aead752f1f87
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