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Fencer Vulns
high 8.5

CVE-2026-17107 json

Cluster-proxy: impersonation-header injection grants cluster-admin on every managed cluster

published 2026-07-24 3 mo ago modified 2026-09-29 40 d ago also EUVD-2026-48728

cvss
8.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

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.

Patch / fix

  • 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

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-17107 updated cvss 8.5

cluster-proxy: Impersonation-header injection grants cluster-admin on every managed cluster

  • Red Hat multicluster engine for Kubernetes 2.6 multicluster-engine/cluster-proxy-rhel9 1783985960
    fixed: vendor fix RHSA-2026:47949
  • Red Hat multicluster engine for Kubernetes 2.8 multicluster-engine/cluster-proxy-rhel9 1784342329
    fixed: vendor fix RHSA-2026:47735
  • Red Hat multicluster engine for Kubernetes 2.9 multicluster-engine/cluster-proxy-rhel9 1783278220
    fixed: vendor fix RHSA-2026:47953
  • Red Hat multicluster engine for Kubernetes 2.10 multicluster-engine/cluster-proxy-rhel9 1784342329
    fixed: vendor fix RHSA-2026:46885
  • Red Hat multicluster engine for Kubernetes 2.11 multicluster-engine/cluster-proxy-rhel9 1784925025
    fixed: vendor fix RHSA-2026:47974
  • Red Hat multicluster engine for Kubernetes 2.17 multicluster-engine/cluster-proxy-rhel9 1784926298
    fixed: vendor fix RHSA-2026:48284
  • Red Hat multicluster engine for Kubernetes 2.6 multicluster-engine/hive-rhel9 1784896768, multicluster-engine/work-rhel9 1784314624, multicluster-engine/discovery-rhel9 1784904558, multicluster-engine/placement-rhel9 1783986737, multicluster-engine/console-mce-rhel9 1784556108, multicluster-engine/must-gather-rhel9 1783985963, +20 more Red Hat multicluster engine for Kubernetes 2.8 multicluster-engine/hive-rhel9 1784896748, multicluster-engine/work-rhel9 1784136764, multicluster-engine/discovery-rhel9 1784306906, multicluster-engine/placement-rhel9 1784332158, multicluster-engine/console-mce-rhel9 1785078604, multicluster-engine/must-gather-rhel9 1784590739, +20 more Red Hat multicluster engine for Kubernetes 2.9 multicluster-engine/hive-rhel9 1783362090, multicluster-engine/work-rhel9 1784677242, multicluster-engine/discovery-rhel9 1783260894, multicluster-engine/placement-rhel9 1784245366, multicluster-engine/console-mce-rhel9 1783348181, multicluster-engine/must-gather-rhel9 1783005291, +23 more Red Hat multicluster engine for Kubernetes 2.10 multicluster-engine/hive-rhel9 1784896750, multicluster-engine/work-rhel9 1784301362, multicluster-engine/discovery-rhel9 1784915379, multicluster-engine/placement-rhel9 1783986002, multicluster-engine/console-mce-rhel9 1784312384, multicluster-engine/must-gather-rhel9 1784849867, +24 more Red Hat multicluster engine for Kubernetes 2.11 multicluster-engine/hive-rhel9 1780918072, multicluster-engine/work-rhel9 1780917940, multicluster-engine/discovery-rhel9 1780586101, multicluster-engine/placement-rhel9 1780918183, multicluster-engine/console-mce-rhel9 1781128292, multicluster-engine/must-gather-rhel9 1781232353, +25 more Red Hat multicluster engine for Kubernetes 2.17 multicluster-engine/hive-rhel9 1780918859, multicluster-engine/work-rhel9 1780711470, multicluster-engine/maestro-rhel9 1781307519, multicluster-engine/discovery-rhel9 1780918592, multicluster-engine/placement-rhel9 1780911300, multicluster-engine/console-mce-rhel9 1780949268, +28 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
3 mo ago

Exploit prediction

0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • Red Hat multicluster engine for Kubernetes 2.10
  • Red Hat multicluster engine for Kubernetes 2.11
  • Red Hat multicluster engine for Kubernetes 2.17
  • Red Hat multicluster engine for Kubernetes 2.6
  • Red Hat multicluster engine for Kubernetes 2.8
  • Red Hat multicluster engine for Kubernetes 2.9

Classification

Weakness
  • CWE-441 Unintended Proxy or Intermediary

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.