{"id":"CVE-2026-4634","revision":"c7a15e4014d1469cb7b80925ac3676b0","records":[{"revision":"c7a15e4014d1469cb7b80925ac3676b0","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-4634","aliases":[],"title":"Keycloak: keycloak: denial of service via excessive processing of openid connect scope parameters","description":"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.","state":0,"publishedAt":"2026-04-02T12:44:53.424+00:00","modifiedAt":"2026-10-06T16:58:54.945+00:00","affected":[{"ecosystem":"https://catalog.redhat.com/software/containers/","name":"rhbk/keycloak-operator-bundle","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat build of Keycloak 26.2\",\n                    \"collectionURL\": \"https://catalog.redhat.com/software/containers/\",\n                    \"packageName\": \"rhbk/keycloak-operator-bundle\",\n                    \"defaultStatus\": \"affected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"26.2.15-1\",\n                            \"lessThan\": \"*\",\n                            \"versionType\": \"rpm\",\n                            \"status\": \"unaffected\"\n                        }\n                    ],\n                    \"cpes\": [\n                        \"cpe:/a:redhat:build_keycloak:26.2::el9\"\n                    ]\n                }"},{"ecosystem":"https://catalog.redhat.com/software/containers/","name":"rhbk/keycloak-rhel9","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat build of Keycloak 26.2\",\n                    \"collectionURL\": \"https://catalog.redhat.com/software/containers/\",\n                    \"packageName\": \"rhbk/keycloak-rhel9\",\n                    \"defaultStatus\": \"affected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"26.2-18\",\n                            \"lessThan\": \"*\",\n                            \"versionType\": \"rpm\",\n                            \"status\": \"unaffected\"\n                        }\n                    ],\n                    \"cpes\": [\n                        \"cpe:/a:redhat:build_keycloak:26.2::el9\"\n                    ]\n                }"},{"ecosystem":"https://catalog.redhat.com/software/containers/","name":"rhbk/keycloak-rhel9-operator","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat build of Keycloak 26.2\",\n                    \"collectionURL\": \"https://catalog.redhat.com/software/containers/\",\n                    \"packageName\": \"rhbk/keycloak-rhel9-operator\",\n                    \"defaultStatus\": \"affected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"26.2-18\",\n                            \"lessThan\": \"*\",\n                            \"versionType\": \"rpm\",\n                            \"status\": \"unaffected\"\n                        }\n                    ],\n                    \"cpes\": [\n                        \"cpe:/a:redhat:build_keycloak:26.2::el9\"\n                    ]\n                }"},{"ecosystem":"https://access.redhat.com/downloads/content/package-browser/","name":"rhbk/keycloak-rhel9","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat build of Keycloak 26.2.15\",\n                    \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"packageName\": \"rhbk/keycloak-rhel9\",\n                    \"cpes\": [\n                        \"cpe:/a:redhat:build_keycloak:26.2::el9\"\n                    ]\n                }"},{"ecosystem":"https://catalog.redhat.com/software/containers/","name":"rhbk/keycloak-operator-bundle","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat build of Keycloak 26.4\",\n                    \"collectionURL\": \"https://catalog.redhat.com/software/containers/\",\n                    \"packageName\": \"rhbk/keycloak-operator-bundle\",\n                    \"defaultStatus\": \"affected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"26.4.11-1\",\n                            \"lessThan\": \"*\",\n                            \"versionType\": \"rpm\",\n                            \"status\": \"unaffected\"\n                        }\n                    ],\n                    \"cpes\": [\n                        \"cpe:/a:redhat:build_keycloak:26.4::el9\"\n                    ]\n                }"},{"ecosystem":"https://catalog.redhat.com/software/containers/","name":"rhbk/keycloak-rhel9","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat build of Keycloak 26.4\",\n                    \"collectionURL\": \"https://catalog.redhat.com/software/containers/\",\n                    \"packageName\": \"rhbk/keycloak-rhel9\",\n                    \"defaultStatus\": \"affected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"26.4-14\",\n                            \"lessThan\": \"*\",\n                            \"versionType\": \"rpm\",\n                            \"status\": \"unaffected\"\n                        }\n                    ],\n                    \"cpes\": [\n                        \"cpe:/a:redhat:build_keycloak:26.4::el9\"\n                    ]\n                }"},{"ecosystem":"https://catalog.redhat.com/software/containers/","name":"rhbk/keycloak-rhel9-operator","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat build of Keycloak 26.4\",\n                    \"collectionURL\": \"https://catalog.redhat.com/software/containers/\",\n                    \"packageName\": \"rhbk/keycloak-rhel9-operator\",\n                    \"defaultStatus\": \"affected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"26.4-14\",\n                            \"lessThan\": \"*\",\n                            \"versionType\": \"rpm\",\n                            \"status\": \"unaffected\"\n                        }\n                    ],\n                    \"cpes\": [\n                        \"cpe:/a:redhat:build_keycloak:26.4::el9\"\n                    ]\n                }"},{"ecosystem":"https://access.redhat.com/downloads/content/package-browser/","name":"rhbk/keycloak-rhel9","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat build of Keycloak 26.4.11\",\n                    \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"packageName\": \"rhbk/keycloak-rhel9\",\n                    \"cpes\": [\n                        \"cpe:/a:redhat:build_keycloak:26.4::el9\"\n                    ]\n                }"},{"ecosystem":"https://access.redhat.com/downloads/content/package-browser/","name":"keycloak-services","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat Single Sign-On 7.6.13\",\n                    \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"packageName\": \"keycloak-services\",\n                    \"cpes\": [\n                        \"cpe:/a:redhat:red_hat_single_sign_on:7.6\"\n                    ]\n                }"},{"ecosystem":"https://access.redhat.com/downloads/content/package-browser/","name":"rh-sso7-keycloak","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat Single Sign-On 7.6 for RHEL 7\",\n                    \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\",\n                    \"packageName\": \"rh-sso7-keycloak\",\n                    \"defaultStatus\": \"affected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0:18.0.20-1.redhat_00001.1.el7sso\",\n                            \"lessThan\": \"*\",\n                            \"versionType\": \"rpm\",\n                            \"status\": \"unaffected\"\n                        }\n                    ],\n                    \"cpes\": [\n                        \"cpe:/a:redhat:red_hat_single_sign_on:7.6::el7\"\n                    ]\n                }"},{"ecosystem":"https://access.redhat.com/downloads/content/package-browser/","name":"rh-sso7-keycloak","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat Single Sign-On 7.6 for RHEL 8\",\n                    \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\",\n                    \"packageName\": \"rh-sso7-keycloak\",\n                    \"defaultStatus\": \"affected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0:18.0.20-1.redhat_00001.1.el8sso\",\n                            \"lessThan\": \"*\",\n                            \"versionType\": \"rpm\",\n                            \"status\": \"unaffected\"\n                        }\n                    ],\n                    \"cpes\": [\n                        \"cpe:/a:redhat:red_hat_single_sign_on:7.6::el8\"\n                    ]\n                }"},{"ecosystem":"https://access.redhat.com/downloads/content/package-browser/","name":"rh-sso7-keycloak","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"Red Hat Single Sign-On 7.6 for RHEL 9\",\n                    \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\",\n                    \"packageName\": \"rh-sso7-keycloak\",\n                    \"defaultStatus\": \"affected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0:18.0.20-1.redhat_00001.1.el9sso\",\n                            \"lessThan\": \"*\",\n                            \"versionType\": \"rpm\",\n                            \"status\": \"unaffected\"\n                        }\n                    ],\n                    \"cpes\": [\n                        \"cpe:/a:redhat:red_hat_single_sign_on:7.6::el9\"\n                    ]\n                }"},{"ecosystem":"https://catalog.redhat.com/software/containers/","name":"rh-sso-7/sso76-openshift-rhel8","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Red Hat\",\n                    \"product\": \"RHEL-8 based Middleware Containers\",\n                    \"collectionURL\": \"https://catalog.redhat.com/software/containers/\",\n                    \"packageName\": \"rh-sso-7/sso76-openshift-rhel8\",\n                    \"defaultStatus\": \"affected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"7.6-85\",\n                            \"lessThan\": \"*\",\n                            \"versionType\": \"rpm\",\n                            \"status\": \"unaffected\"\n                        }\n                    ],\n                    \"cpes\": [\n                        \"cpe:/a:redhat:rhosemc:1.0::el8\"\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://access.redhat.com/errata/RHSA-2026:6475","https://access.redhat.com/errata/RHSA-2026:6476","https://access.redhat.com/errata/RHSA-2026:6477","https://access.redhat.com/errata/RHSA-2026:6478","https://access.redhat.com/errata/RHSA-2026:76128","https://access.redhat.com/errata/RHSA-2026:76129","https://access.redhat.com/errata/RHSA-2026:76130","https://access.redhat.com/errata/RHSA-2026:76132","https://access.redhat.com/errata/RHSA-2026:76134","https://access.redhat.com/security/cve/CVE-2026-4634","https://bugzilla.redhat.com/show_bug.cgi?id=2450250"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-4634","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-4634","identifiers":["CVE-2026-4634"]},"retained":false,"historicalAffected":[]}],"coverage":[]}