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CRITICAL

CVE-2026-66794

CVSS v3

9.3

CRITICAL

EPSS Score

0.6 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2026-66794 Red Hat Product Security24 products fixed

    cluster-proxy-addon: cluster-proxy-addon: unauthenticated SSRF to arbitrary managed-cluster services via public Route

  • RHSA-2026:59593 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: multicluster engine for Kubernetes v2.17.2 security update

  • RHSA-2026:59579 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: multicluster engine for Kubernetes v2.6.14 security update

  • RHSA-2026:59559 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: multicluster engine for Kubernetes v2.9.7 security update

  • RHSA-2026:59558 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: multicluster engine for Kubernetes v2.8.10 security update

  • RHSA-2026:59557 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: multicluster engine for Kubernetes v2.10.6 security update

1 more advisory

Full record on NVD

Description

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
Published
2026-08-19
Last Modified
2026-08-20

Frequently asked questions

What is CVE-2026-66794?

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.

Is CVE-2026-66794 actively exploited?

Active exploitation of CVE-2026-66794 has not been confirmed. Its EPSS score was 0.6% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-66794?

CVE-2026-66794 has a CVSS v3 base score of 9.3 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N.

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