HighCVE-2026-17107

    Cluster-proxy: impersonation-header injection grants cluster-admin on every managed cluster (CVE-2026-17107)

    Published Last modified Sources: Red Hat, CVE.org

    What is affected, what to do

    A flaw was found in the cluster-proxy service-proxy component used in Red Hat Advanced Cluster Management for Kubernetes (RHACM) and multicluster-engine (MCE). The service-proxy appends impersonation group headers to proxied requests without first removing caller-supplied values, and the spoke ServiceAccount holds unrestricted impersonation permissions.

    Update Red Hat multicluster engine for Kubernetes 2.10 to version 1784342329, Red Hat multicluster engine for Kubernetes 2.11 to version 1784925025, Red Hat multicluster engine for Kubernetes 2.17 to version 1784926298.

    Affected
    • Red Hat multicluster engine for Kubernetes 2.10 lt *..1784342329
    • Red Hat multicluster engine for Kubernetes 2.11 lt *..1784925025
    • Red Hat multicluster engine for Kubernetes 2.17 lt *..1784926298
    • Red Hat multicluster engine for Kubernetes 2.6 lt *..1783985960
    • Red Hat multicluster engine for Kubernetes 2.8 lt *..1784342329
    • Red Hat multicluster engine for Kubernetes 2.9 lt *..1783278220
    Fixed in
    • Red Hat multicluster engine for Kubernetes 2.10 1784342329
    • Red Hat multicluster engine for Kubernetes 2.11 1784925025
    • Red Hat multicluster engine for Kubernetes 2.17 1784926298
    • Red Hat multicluster engine for Kubernetes 2.6 1783985960
    • Red Hat multicluster engine for Kubernetes 2.8 1784342329
    • Red Hat multicluster engine for Kubernetes 2.9 1783278220

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

    Metrics

    8.5

    Priority

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

    Source: NVD, CVSS v3

    8.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: Red Hat, CVE.org

    0.6 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 46.8

    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
    81.62 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
    8.5 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
    8.5
    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
    0.6 %
    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
    46.8
    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
    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-441

    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 cluster-proxy service-proxy component used in Red Hat Advanced Cluster Management for Kubernetes (RHACM) and multicluster-engine (MCE). The service-proxy appends impersonation group headers to proxied requests without first removing caller-supplied values, and the spoke ServiceAccount holds unrestricted impersonation permissions. An authenticated hub principal can inject an Impersonate-Group header to escalate to cluster-admin on every managed cluster.

    Source: redhat_csaf, cvelistv5, NVD (NIST)

    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
    Red Hatmulticluster engine for Kubernetes 2.10
    • < 1784342329
    • 1784342329
    Red Hatmulticluster engine for Kubernetes 2.11
    • < 1784925025
    • 1784925025
    Red Hatmulticluster engine for Kubernetes 2.17
    • < 1784926298
    • 1784926298
    Red Hatmulticluster engine for Kubernetes 2.6
    • < 1783985960
    • 1783985960
    Red Hatmulticluster engine for Kubernetes 2.8
    • < 1784342329
    • 1784342329
    Red Hatmulticluster engine for Kubernetes 2.9
    • < 1783278220
    • 1783278220

    Vendors and products

    Weakness classes (CWE)

    • CWE-441Unintended Proxy or Intermediary ('Confused Deputy')

      Class

      The product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor.

      Entry at MITRE CWE-441

    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 modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
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      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/17xxx/CVE-2026-17107.json">CVE-2026-17107</a>

      Source identifier: secalert@redhat.com

    2. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/17xxx/CVE-2026-17107.json">CVE-2026-17107</a>

      Source identifier: secalert@redhat.com

    3. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
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      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/17xxx/CVE-2026-17107.json">CVE-2026-17107</a>

      Source identifier: secalert@redhat.com

    4. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/17xxx/CVE-2026-17107.json">CVE-2026-17107</a>

      Source identifier: secalert@redhat.com

    5. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
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      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/17xxx/CVE-2026-17107.json">CVE-2026-17107</a>

      Source identifier: secalert@redhat.com

    Show 14 older changes

    1. Record modifiedRed Hat

      Show 19 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
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      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/17xxx/CVE-2026-17107.json">CVE-2026-17107</a>
      Referenceadded
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      https://access.redhat.com/errata/RHSA-2026:46885
      Referenceadded
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      https://access.redhat.com/errata/RHSA-2026:47388
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      https://access.redhat.com/errata/RHSA-2026:47735
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      https://access.redhat.com/errata/RHSA-2026:47949
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      https://access.redhat.com/errata/RHSA-2026:47953
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      https://access.redhat.com/errata/RHSA-2026:47974
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      https://access.redhat.com/errata/RHSA-2026:48284
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      https://access.redhat.com/security/cve/CVE-2026-17107
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      https://bugzilla.redhat.com/show_bug.cgi?id=2506771
      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:46885
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      https://access.redhat.com/errata/RHSA-2026:47388
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      https://access.redhat.com/errata/RHSA-2026:47735
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      https://access.redhat.com/errata/RHSA-2026:47949
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      https://access.redhat.com/errata/RHSA-2026:47953
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      https://access.redhat.com/errata/RHSA-2026:47974
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      Referenceremoved
      https://access.redhat.com/errata/RHSA-2026:48284
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      Referenceremoved
      https://access.redhat.com/security/cve/CVE-2026-17107
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      Referenceremoved
      https://bugzilla.redhat.com/show_bug.cgi?id=2506771
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      Source identifier: secalert@redhat.com

    2. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)
      multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.11.0 (+4)

      Source identifier: secalert@redhat.com

    3. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)

      Source identifier: secalert@redhat.com

    4. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.11 (+4)
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)

      Source identifier: secalert@redhat.com

    5. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)
      multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.11 (+4)

      Source identifier: secalert@redhat.com

    6. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)

      Source identifier: secalert@redhat.com

    7. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11.0 (+4)
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)

      Source identifier: secalert@redhat.com

    8. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11.0 (+4)

      Source identifier: secalert@redhat.com

    9. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11.0 (+4)
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)

      Source identifier: secalert@redhat.com

    10. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11.0 (+4)

      Source identifier: secalert@redhat.com

    11. Record modifiedRed Hat

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.11 (+4)
      multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.1, multicluster engine for Kubernetes 2.11 (+4)

      Source identifier: secalert@redhat.com

    12. Record modifiedRed Hat

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:47949
      Referenceadded
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      https://access.redhat.com/errata/RHSA-2026:47974
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.8 (+1)
      multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.11 (+3)

      Source identifier: secalert@redhat.com

    13. Record modifiedRed Hat

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:47735
      Affected versions (publisher)changed
      multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.10
      multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.10, multicluster engine for Kubernetes 2.8

      Source identifier: secalert@redhat.com

    14. Record modifiedRed Hat

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://access.redhat.com/errata/RHSA-2026:46885
      Affected versions (publisher)changed
      Multicluster Engine for Kubernetes
      multicluster engine for Kubernetes 2.10

      Source identifier: secalert@redhat.com

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