{"id":"GHSA-q4gv-pjmh-c735","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.","aliases":["CVE-2026-4740","GO-2026-5564"],"modified":"2026-06-25T23:11:37.113218915Z","published":"2026-04-07T15:30:52Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-04-08T19:13:58Z","nvd_published_at":"2026-04-07T15:17:46Z","cwe_ids":["CWE-295"],"severity":"HIGH"},"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"}],"affected":[{"package":{"name":"open-cluster-management.io/ocm","ecosystem":"Go","purl":"pkg:golang/open-cluster-management.io/ocm"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.2.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-q4gv-pjmh-c735/GHSA-q4gv-pjmh-c735.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H"}]}