Vulnerability in Red Hat Multicluster Engine For Kubernetes

CVE-2026-4740

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.

Vulnerability class: Improper Certificate Validation

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.001 (4.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 4th percentile — 4.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-4740: held from 0.002 to 0.001.

EPSS over last 30 days · oldest: 0.002 · newest: 0.001 · change: -0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-4740?
CVE-2026-4740 is a high-severity vulnerability in Red Hat Multicluster Engine For Kubernetes, classified under Improper Certificate Validation. CVSS score: 8.2/10. Published 2026-04-07.
How severe is CVE-2026-4740?
High severity. CVSS v3 base score is 8.2 out of 10.