Cluster-proxy-addon: cluster-proxy-addon: unauthenticated ssrf to arbitrary managed-cluster services via public route

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-66794
StatePUBLISHED
Assignerredhat
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-19 18:17:16 UTC
Updated2026-08-21 20:16:39 UTC
DescriptionA 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.

Risk And Classification

Primary CVSS: v3.1 9.3 CRITICAL from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

EPSS: 0.003200000 probability, percentile 0.249270000 (date 2026-08-20)

Problem Types: CWE-918 | CWE-918 Server-Side Request Forgery (SSRF)

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary9.3CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
3.1CNACVSS9.3CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Red Hat Multicluster Engine For Kubernetes Not specified Not specified
CNA Red Hat Multicluster Engine For Kubernetes Not specified Not specified

References

ReferenceSourceLinkTags
access.redhat.com/security/cve/CVE-2026-66794 [email protected] access.redhat.com
bugzilla.redhat.com/show_bug.cgi [email protected] bugzilla.redhat.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

SourceTimeEvent
CNA2026-07-27T00:00:00.000ZReported to Red Hat.
CNA2026-08-19T14:00:00.000ZMade public.

Workarounds

CNA: To mitigate this issue, restrict network access to the user-facing Route of the `cluster-proxy-addon` to trusted networks only. Implement firewall rules to limit inbound connections to the Route's exposed port, ensuring only authorized sources can reach it. This reduces the attack surface by preventing unauthenticated external access to the vulnerable proxy.

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