CVE-2026-4740Rhacm: open cluster management (ocm): cross-cluster privilege escalation via improper kubernetes client certificate renewal validation
Updated under an hour ago ()
Does this affect you?
It affects Red Hat multicluster engine for Kubernetes 2.1 and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 8.2 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
- Weakness (CWE)
- CWE-295
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- redhat
- NVD analysis
- Modified
- Record last updated
- Sep 9, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Red Hat multicluster engine for Kubernetes 2.1 redhat:multicluster_engine | from 1776881164 not affected | CNA record |
Red Hat multicluster engine for Kubernetes 2.1 redhat:multicluster_engine | from 1776881164 not affected | CISA ADP |
redhat advanced_cluster_management_for_kubernetes redhat:advanced_cluster_management_for_kubernetes | all versions | NVD |
References
- https://access.redhat.com/errata/RHSA-2026:11414vendor-advisory, x-refsource-redhat
- https://access.redhat.com/errata/RHSA-2026:13542vendor-advisory, x-refsource-redhat
- https://access.redhat.com/errata/RHSA-2026:13853vendor-advisory, x-refsource-redhat
- https://access.redhat.com/errata/RHSA-2026:8218vendor-advisory, x-refsource-redhat
- https://access.redhat.com/errata/RHSA-2026:9848vendor-advisory, x-refsource-redhat
- https://access.redhat.com/security/cve/CVE-2026-4740vdb-entry, x-refsource-redhat, vendor-advisory
- https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape/exploit, third-party-advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2450590issue-tracking, x-refsource-redhat, vendor-advisory
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4740.json
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.