high8.2
CVE-2026-4740
Open Cluster Management (OCM): Cross-cluster privilege escalation via improper Kubernetes client certificate renewal validation
Impact
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
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| go | open-cluster-management.io/ocm | < 1.2.1 | 1.2.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Redhat | Advanced Cluster Management For Kubernetes | All versions |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://access.redhat.com/errata/RHSA-2026:11414
- https://access.redhat.com/errata/RHSA-2026:13542
- https://access.redhat.com/errata/RHSA-2026:13853
- https://access.redhat.com/errata/RHSA-2026:8218
- https://access.redhat.com/errata/RHSA-2026:9848
- https://access.redhat.com/security/cve/CVE-2026-4740
- https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape/
- https://bugzilla.redhat.com/show_bug.cgi?id=2450590
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4740.json
- https://github.com/advisories/GHSA-q4gv-pjmh-c735
- https://nvd.nist.gov/vuln/detail/CVE-2026-4740
- https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape
- https://github.com/open-cluster-management-io/ocm/commit/9e70cc1e21a15239c81111062c0b37df4b5a8026