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.
Published: 2026-04-07
Score: 8.2 High
EPSS: < 1% Very Low
KEV: No
Impact: Cross‑cluster privilege escalation
Action: Immediate Patch
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Remediation

Vendor Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-q4gv-pjmh-c735 Open Cluster Management (OCM): Cross-cluster privilege escalation via improper Kubernetes client certificate renewal validation
History

Tue, 28 Apr 2026 20:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat advanced Cluster Management For Kubernetes
CPEs cpe:2.3:a:redhat:advanced_cluster_management_for_kubernetes:-:*:*:*:*:*:*:*
Vendors & Products Redhat advanced Cluster Management For Kubernetes

Thu, 09 Apr 2026 15:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 08 Apr 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Tue, 07 Apr 2026 15:15:00 +0000

Type Values Removed Values Added
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.
Title Rhacm: open cluster management (ocm): cross-cluster privilege escalation via improper kubernetes client certificate renewal validation
First Time appeared Redhat
Redhat multicluster Engine
Weaknesses CWE-295
CPEs cpe:/a:redhat:multicluster_engine
Vendors & Products Redhat
Redhat multicluster Engine
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H'}


Subscriptions

Redhat Advanced Cluster Management For Kubernetes Multicluster Engine
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-04-09T14:40:43.580Z

Reserved: 2026-03-24T03:19:46.998Z

Link: CVE-2026-4740

cve-icon Vulnrichment

Updated: 2026-04-09T14:40:40.356Z

cve-icon NVD

Status : Analyzed

Published: 2026-04-07T15:17:46.797

Modified: 2026-04-28T20:39:15.040

Link: CVE-2026-4740

cve-icon Redhat

Severity : Important

Publid Date: 2026-04-07T14:00:35Z

Links: CVE-2026-4740 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-08T19:48:47Z

Weaknesses