{"id":"CVE-2026-4740","aliases":["GO-2026-5564"],"url":"https://o3.security/vulnerability/CVE-2026-4740","summary":"Open Cluster Management (OCM): Cross-cluster privilege escalation via improper Kubernetes client certificate renewal validation","details":"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":"2026-04-07T15:30:52Z","modified":"2026-06-25T23:11:37.113218915Z","cvss":{"score":8.2,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"open-cluster-management.io/ocm","fixedVersion":"1.2.1"}],"fix":{"url":"https://github.com/open-cluster-management-io/ocm/commit/9e70cc1e21a15239c81111062c0b37df4b5a8026","label":"open-cluster-management-io/ocm@9e70cc1"},"references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-4740"},{"type":"WEB","url":"https://github.com/open-cluster-management-io/ocm/commit/9e70cc1e21a15239c81111062c0b37df4b5a8026"},{"type":"WEB","url":"https://access.redhat.com/security/cve/CVE-2026-4740"},{"type":"WEB","url":"https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape"},{"type":"WEB","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2450590"},{"type":"PACKAGE","url":"https://github.com/open-cluster-management-io/OCM"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-06-25T23:11:37.113218915Z"}}