Cluster-proxy-addon: cluster-proxy-addon: unauthenticated ssrf to arbitrary managed-cluster services via public route
Priority MEDIUM 47CWE-918Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
A flaw was found in the `cluster-proxy-addon` component of Multicluster Engine for Kubernetes. This vulnerability allows an unauthenticated attacker, who can access the user-facing route, to bypass authentication and authorization checks. By manipulating URL path segments, the attacker can proxy requests to arbitrary services across any managed cluster. This enables unauthorized access to internal services that would otherwise be protected, potentially leading to information disclosure or further compromise of the cluster environment.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00621 50th percentileScored 2026-11-07
Fix Fixed Red Hat: 6 advisories
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Red Hat | multicluster engine for Kubernetes 2.10 | — | 1787173361 | Patch available | CNA |
| Red Hat | multicluster engine for Kubernetes 2.11 | — | 1787276784 | Patch available | CNA |
| Red Hat | multicluster engine for Kubernetes 2.17 | — | 1786983349 | Patch available | CNA |
| Red Hat | multicluster engine for Kubernetes 2.6 | — | 1787275318 | Patch available | CNA |
| Red Hat | multicluster engine for Kubernetes 2.8 | — | 1787275519 | Patch available | CNA |
| Red Hat | multicluster engine for Kubernetes 2.9 | — | 1787274923 | Patch available | CNA |
- multicluster engine for Kubernetes 2.10 VendorRed Hat Affected — Fixed in 1787173361 Patch available CNA
- multicluster engine for Kubernetes 2.11 VendorRed Hat Affected — Fixed in 1787276784 Patch available CNA
- multicluster engine for Kubernetes 2.17 VendorRed Hat Affected — Fixed in 1786983349 Patch available CNA
- multicluster engine for Kubernetes 2.6 VendorRed Hat Affected — Fixed in 1787275318 Patch available CNA
- multicluster engine for Kubernetes 2.8 VendorRed Hat Affected — Fixed in 1787275519 Patch available CNA
- multicluster engine for Kubernetes 2.9 VendorRed Hat Affected — Fixed in 1787274923 Patch available CNA
CPE names CNA · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:/a:redhat:multicluster_engine:2.10::el9 | 2.10 | — | Red Hat |
| cpe:/a:redhat:multicluster_engine:2.11::el9 | 2.11 | — | Red Hat |
| cpe:/a:redhat:multicluster_engine:2.17::el9 | 2.17 | — | Red Hat |
| cpe:/a:redhat:multicluster_engine:2.6::el9 | 2.6 | — | Red Hat |
| cpe:/a:redhat:multicluster_engine:2.8::el9 | 2.8 | — | Red Hat |
| cpe:/a:redhat:multicluster_engine:2.9::el9 | 2.9 | — | Red Hat |
- cpe:/a:redhat:multicluster_engine:2.10::el9 Versions 2.10 — ·Red Hat
- cpe:/a:redhat:multicluster_engine:2.11::el9 Versions 2.11 — ·Red Hat
- cpe:/a:redhat:multicluster_engine:2.17::el9 Versions 2.17 — ·Red Hat
- cpe:/a:redhat:multicluster_engine:2.6::el9 Versions 2.6 — ·Red Hat
- cpe:/a:redhat:multicluster_engine:2.8::el9 Versions 2.8 — ·Red Hat
- cpe:/a:redhat:multicluster_engine:2.9::el9 Versions 2.9 — ·Red Hat
Remediation
Red Hat 6 advisories
- RHSA-2026:59593 Released 2026-08-25 · Red Hat rating Importantmulticluster engine for Kubernetes v2.17.2 security update
- multicluster engine for Kubernetes 2.17 registry.redhat.io/multicluster-engine/cluster-api-provider-kubevirt-rhel9, registry.redhat.io/multicluster-engine/cluster-curator-controller-rhel9, registry.redhat.io/multicluster-engine/cluster-image-set-controller-rhel9 +6
- RHSA-2026:59579 Released 2026-08-25 · Red Hat rating Importantmulticluster engine for Kubernetes v2.6.14 security update
- multicluster engine for Kubernetes 2.6 registry.redhat.io/multicluster-engine/addon-manager-rhel9, registry.redhat.io/multicluster-engine/cluster-curator-controller-rhel9, registry.redhat.io/multicluster-engine/cluster-image-set-controller-rhel9 +17
- RHSA-2026:59559 Released 2026-08-25 · Red Hat rating Importantmulticluster engine for Kubernetes v2.9.7 security update
- multicluster engine for Kubernetes 2.9 registry.redhat.io/multicluster-engine/addon-manager-rhel9, registry.redhat.io/multicluster-engine/cluster-curator-controller-rhel9, registry.redhat.io/multicluster-engine/cluster-image-set-controller-rhel9 +15
Show 3 more Red Hat advisories
- RHSA-2026:59558 Released 2026-08-25 · Red Hat rating Importantmulticluster engine for Kubernetes v2.8.10 security update
- multicluster engine for Kubernetes 2.8 registry.redhat.io/multicluster-engine/addon-manager-rhel9, registry.redhat.io/multicluster-engine/backplane-rhel9-operator, registry.redhat.io/multicluster-engine/cluster-api-provider-agent-rhel9 +20
- RHSA-2026:59557 Released 2026-08-25 · Red Hat rating Importantmulticluster engine for Kubernetes v2.10.6 security update
- multicluster engine for Kubernetes 2.10 registry.redhat.io/multicluster-engine/addon-manager-rhel9, registry.redhat.io/multicluster-engine/cluster-curator-controller-rhel9, registry.redhat.io/multicluster-engine/cluster-image-set-controller-rhel9 +16
- RHSA-2026:59556 Released 2026-08-25 · Red Hat rating Importantmulticluster engine for Kubernetes v2.11.6 security update
- multicluster engine for Kubernetes 2.11 registry.redhat.io/multicluster-engine/addon-manager-rhel9, registry.redhat.io/multicluster-engine/cluster-curator-controller-rhel9, registry.redhat.io/multicluster-engine/cluster-image-set-controller-rhel9 +14
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| multicluster engine for Kubernetes 2.10 | Fixed | RHSA-2026:59557 |
| multicluster engine for Kubernetes 2.11 | Fixed | RHSA-2026:59556 |
| multicluster engine for Kubernetes 2.17 | Fixed | RHSA-2026:59593 |
| multicluster engine for Kubernetes 2.6 | Fixed | RHSA-2026:59579 |
| multicluster engine for Kubernetes 2.8 | Fixed | RHSA-2026:59558 |
| multicluster engine for Kubernetes 2.9 | Fixed | RHSA-2026:59559 |
Not affected: 6 products
- multicluster engine for Kubernetes 2.10
- 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
Timeline
- 2026-10-02 Threatist record created from CVE-2026-66794
- 2026-10-03 Alias added: GHSA-9855-9cch-x8mw
- 2026-11-07 EPSS moved to the 50th–90th percentile
References
More Red Hat vulnerabilities
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- TI-2018-16080 A code execution vulnerability exists in the Stapler web framework used by Jenkins 2.153… KEVCVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-66794 · CVE Program
- CVE-2026-66794 · NVD
- FIRST EPSS
- GHSA-9855-9cch-x8mw · GitHub Advisory Database · CC BY 4.0
- CVE-2026-66794 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences