{"id":"CVE-2026-4740","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-4740","summary":"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…","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":"2026-04-07T15:17:46.797","modified":"2026-07-15T02:22:52.567","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":[],"fix":null,"references":[{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-4740"},{"type":"EXPLOIT","url":"https://blog.arfevrier.fr/open-cluster-management-cross-cluster-escape/"},{"type":"ADVISORY","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2450590"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-4740"},{"type":"ADVISORY","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2450590"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4740.json"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T02:22:52.567"}}