Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
Unauthenticated remote SSRF via crafted path (AV:N/AC:L/PR:N/UI:N); scope changes as the hub proxy reaches managed clusters (S:C) with high read exposure (C:H), limited integrity (I:L), no availability impact.
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
Lifecycle Timeline
2DescriptionCVE.org
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.
Articles & Coverage 1
AnalysisAI
Authentication and authorization bypass in the cluster-proxy-addon component of Red Hat's Multicluster Engine for Kubernetes (MCE) lets an unauthenticated attacker who can reach the user-facing proxy route manipulate URL path segments to proxy requests to arbitrary services on any managed cluster. Because the flaw is a server-side request forgery (CWE-918) with a changed CVSS scope, a request to the hub's exposed route pivots into internal services on downstream clusters that were never meant to be externally reachable, enabling information disclosure and potential further compromise. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires network reachability to the MCE hub's user-facing cluster-proxy-addon route and the ability to craft URL path segments that select a target service and managed cluster; per the CVSS vector (PR:N/UI:N) it is unauthenticated and needs no user interaction. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The signals point to a genuine high-priority issue rather than an inflated score: the CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N, 9.3) describes remote, low-complexity, unauthenticated exploitation with a scope change reflecting cross-cluster reach, which is exactly what the SSRF/auth-bypass description supports - the metrics and the narrative are consistent. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker who can reach the internet-exposed MCE hub proxy route sends an HTTP request with crafted URL path segments that name an internal service on a managed cluster. The proxy bypasses authorization and forwards the request, returning data from an internal API or service (for example a cluster's internal metadata or admin endpoint) to the unauthenticated attacker. … |
| Remediation | Apply the fixed cluster-proxy-addon/MCE release identified in the Red Hat erratum once available and monitor https://access.redhat.com/security/cve/CVE-2026-66794 for the exact patched version, as no specific fix version is provided in the available data (patch status per vendor advisory; released patched version not independently confirmed here). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Inventory all Red Hat MCE deployments and restrict external access to cluster-proxy-addon routes via firewall or network controls. …
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View allSame technique Information Disclosure
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-62598
GHSA-9855-9cch-x8mw