CVE-2026-17107
HIGH 8.5A 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.
Severe if exploited (CVSS 8.5), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 28th percentile
Impact if exploited
8.5CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ⚠Complexity: Needs a race window or specific setup
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-17107/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-17107/poc.json
Affected
Vendors Red Hat
Products Multicluster Engine For Kubernetes 2.1 Multicluster Engine For Kubernetes 2.11 Multicluster Engine For Kubernetes 2.17 Multicluster Engine For Kubernetes 2.6 Multicluster Engine For Kubernetes 2.8 Multicluster Engine For Kubernetes 2.9.0
Weakness (CWE)
- CWE-441: Unintended Proxy or Intermediary ('Confused Deputy')
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
All CVSS metrics
- HIGH 8.5 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H - HIGH 8.5 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
References
Advisories
- https://access.redhat.com/errata/RHSA-2026:46885
- https://access.redhat.com/errata/RHSA-2026:47388
- https://access.redhat.com/errata/RHSA-2026:47735
- https://access.redhat.com/errata/RHSA-2026:47949
- https://access.redhat.com/errata/RHSA-2026:47953
- https://access.redhat.com/errata/RHSA-2026:47974
- https://access.redhat.com/errata/RHSA-2026:48284