CVE-2026-66794Network attack vector

Unauthenticated SSRF via client-controlled proxy target

Published Aug 19, 2026 · Updated Aug 25, 2026

SSRF in Red Hat multicluster engine for Kubernetes allows remote attackers to reach managed-cluster services through a user-facing route. The cluster-proxy-addon user-server ServeHTTP handler builds the target host from client-controlled namespace, service, and port path segments without authentication, authorization, or an allowlist. Reachability of the exposed route is sufficient to read responses from otherwise protected internal services across managed clusters; no availability impact is demonstrated.

CVSS severity9.3
Critical
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Red Hat multicluster engine for Kubernetes allows remote attackers to reach managed-cluster services through a user-facing route. The cluster-proxy-addon user-server ServeHTTP handler builds the target host from client-controlled namespace, service, and port path segments without authentication, authorization, or an allowlist. Reachability of the exposed route is sufficient to read responses from otherwise protected internal services across managed clusters; no availability impact is demonstrated.

The record

CVE
CVE-2026-66794
Published
Aug 19, 2026
Updated
Aug 25, 2026
Vendor
389 Directory Server
Product
multicluster engine for Kubernetes
Classifications
CWE-918, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

389 Directory Server · multicluster engine for KubernetesAffected versions are unavailable in this record.

Published CVSS scores

9.3Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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