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.
References9
- access.redhat.com/errata/RHSA-2026:46885
- access.redhat.com/errata/RHSA-2026:47388
- access.redhat.com/errata/RHSA-2026:47735
- access.redhat.com/errata/RHSA-2026:47949
- access.redhat.com/errata/RHSA-2026:47953
- access.redhat.com/errata/RHSA-2026:47974
- access.redhat.com/errata/RHSA-2026:48284
- access.redhat.com/security/cve/CVE-2026-17107
- bugzilla.redhat.com/show_bug.cgi?id=2506771
Metrics
- CVSS 3.1
-
8.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H - EPSS — exploit probability
- 1% percentile: 48 · as of 14 November 2026
- CWE
- CWE-441
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