{"id":"CVE-2026-4634","aliases":["GHSA-h4wv-g838-66g3"],"url":"https://o3.security/vulnerability/CVE-2026-4634","summary":"Keycloak: keycloak: denial of service via excessive processing of openid connect scope parameters","details":"A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.","published":"2026-08-25T11:42:30.857Z","modified":"2026-09-08T08:48:06.811563105Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Bitnami","name":"keycloak","fixedVersion":"26.2.1"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6475"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6476"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6477"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:6478"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-4634"},{"type":"ADVISORY","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2450250"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-4634"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4634.json"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-08T08:48:06.811563105Z"}}