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Vulnerability · Published Apr 7, 2026 · Assigned by redhat

CVE-2026-4740Rhacm: open cluster management (ocm): cross-cluster privilege escalation via improper kubernetes client certificate renewal validation

High 8.2

In plain English

A high-severity improper certificate validation in Multicluster Engine for Kubernetes from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 4% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.2High
Exploit odds (30 days)0.2%top 95.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

A flaw was found in Open Cluster Management (OCM), the technology underlying Red Hat Advanced Cluster Management (ACM). Improper validation of Kubernetes client certificate renewal allows a managed cluster administrator to forge a client certificate that can be approved by the OCM controller. This enables cross-cluster privilege escalation and may allow an attacker to gain control over other managed clusters, including the hub cluster.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Goopen-cluster-management.io/ocm1.2.1GHSA-q4gv-pjmh-c735
Goopen-cluster-management.io/ocm1.2.1GO-2026-5564

Affected products (as reported)

VendorProductVersions
Red Hat multicluster engine for Kubernetes 2.1 see references
Red Hat multicluster engine for Kubernetes 2.11 see references
Red Hat multicluster engine for Kubernetes 2.6 see references
Red Hat multicluster engine for Kubernetes 2.8 see references
Red Hat multicluster engine for Kubernetes 2.9 see references
Red Hat Multicluster Engine for Kubernetes see references
Red Hat Multicluster Engine for Kubernetes see references
Red Hat Multicluster Engine for Kubernetes see references
Red Hat Multicluster Engine for Kubernetes see references
Red Hat Multicluster Engine for Kubernetes see references
Red Hat Multicluster Engine for Kubernetes see references

Weakness: CWE-295 · Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

References