{"id":"CVE-2023-6563","details":"An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (\u003e 500,000 users with each having at least 2 saved sessions). If an attacker creates two or more user sessions and then open the \"consents\" tab of the admin User Interface, the UI attempts to load a huge number of offline client sessions leading to excessive memory and CPU consumption which could potentially crash the entire system.","aliases":["GHSA-54f3-c6hg-865h"],"modified":"2026-04-10T05:07:39.408984Z","published":"2023-12-14T18:15:45.540Z","references":[{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2023-6563"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2023:7854"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2023:7855"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2023:7856"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2023:7858"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2253308"},{"type":"REPORT","url":"https://github.com/keycloak/keycloak/issues/13340"},{"type":"EVIDENCE","url":"https://access.redhat.com/errata/RHSA-2023:7857"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/keycloak/keycloak","events":[{"introduced":"0"},{"fixed":"315f02483279cdaa2634742c039b4cf8111d18ef"}],"database_specific":{"versions":[{"introduced":"0"},{"fixed":"21.0.0"}]}}],"versions":["1.0-alpha-1","1.0-alpha-1-12062013","1.0-alpha-2","1.0-alpha-3","1.0-beta-1","1.0-beta-2","1.0-beta-4","1.0-final","1.0-rc-1","1.0.0.Final","1.1.0.Beta2","1.3.0.Final","2.4.0.Test"],"database_specific":{"unresolved_ranges":[{"events":[{"introduced":"0"},{"last_affected":"7.6"}]},{"events":[{"introduced":"0"},{"last_affected":"4.11"}]},{"events":[{"introduced":"0"},{"last_affected":"4.12"}]},{"events":[{"introduced":"0"},{"last_affected":"4.9"}]},{"events":[{"introduced":"0"},{"last_affected":"4.10"}]},{"events":[{"introduced":"0"},{"last_affected":"4.9"}]},{"events":[{"introduced":"0"},{"last_affected":"4.10"}]}],"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-6563.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H"}]}