{
  "threat_severity" : "Important",
  "public_date" : "2026-04-02T12:30:00Z",
  "bugzilla" : {
    "description" : "keycloak: Keycloak: Denial of Service via excessive processing of OpenID Connect scope parameters",
    "id" : "2450250",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2450250"
  },
  "cvss3" : {
    "cvss3_base_score" : "7.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-1050",
  "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.", "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." ],
  "statement" : "This is an Important denial of service vulnerability in Red Hat Build of Keycloak (RHBK). An unauthenticated attacker can exploit this flaw by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect token endpoint, leading to high resource consumption and prolonged processing times on the Keycloak server.",
  "acknowledgement" : "Red Hat would like to thank Slvrqn for reporting this issue.",
  "affected_release" : [ {
    "product_name" : "Red Hat build of Keycloak 26.2",
    "release_date" : "2026-04-02T00:00:00Z",
    "advisory" : "RHSA-2026:6476",
    "cpe" : "cpe:/a:redhat:build_keycloak:26.2::el9",
    "package" : "rhbk/keycloak-operator-bundle:26.2.15-1"
  }, {
    "product_name" : "Red Hat build of Keycloak 26.2",
    "release_date" : "2026-04-02T00:00:00Z",
    "advisory" : "RHSA-2026:6476",
    "cpe" : "cpe:/a:redhat:build_keycloak:26.2::el9",
    "package" : "rhbk/keycloak-rhel9:26.2-18"
  }, {
    "product_name" : "Red Hat build of Keycloak 26.2",
    "release_date" : "2026-04-02T00:00:00Z",
    "advisory" : "RHSA-2026:6476",
    "cpe" : "cpe:/a:redhat:build_keycloak:26.2::el9",
    "package" : "rhbk/keycloak-rhel9-operator:26.2-18"
  }, {
    "product_name" : "Red Hat build of Keycloak 26.2.15",
    "release_date" : "2026-04-02T00:00:00Z",
    "advisory" : "RHSA-2026:6475",
    "cpe" : "cpe:/a:redhat:build_keycloak:26.2::el9",
    "package" : "rhbk/keycloak-rhel9"
  }, {
    "product_name" : "Red Hat build of Keycloak 26.4",
    "release_date" : "2026-04-02T00:00:00Z",
    "advisory" : "RHSA-2026:6478",
    "cpe" : "cpe:/a:redhat:build_keycloak:26.4::el9",
    "package" : "rhbk/keycloak-operator-bundle:26.4.11-1"
  }, {
    "product_name" : "Red Hat build of Keycloak 26.4",
    "release_date" : "2026-04-02T00:00:00Z",
    "advisory" : "RHSA-2026:6478",
    "cpe" : "cpe:/a:redhat:build_keycloak:26.4::el9",
    "package" : "rhbk/keycloak-rhel9:26.4-14"
  }, {
    "product_name" : "Red Hat build of Keycloak 26.4",
    "release_date" : "2026-04-02T00:00:00Z",
    "advisory" : "RHSA-2026:6478",
    "cpe" : "cpe:/a:redhat:build_keycloak:26.4::el9",
    "package" : "rhbk/keycloak-rhel9-operator:26.4-14"
  }, {
    "product_name" : "Red Hat build of Keycloak 26.4.11",
    "release_date" : "2026-04-02T00:00:00Z",
    "advisory" : "RHSA-2026:6477",
    "cpe" : "cpe:/a:redhat:build_keycloak:26.4::el9",
    "package" : "rhbk/keycloak-rhel9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-4634\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-4634" ],
  "name" : "CVE-2026-4634",
  "mitigation" : {
    "value" : "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.",
    "lang" : "en:us"
  },
  "csaw" : false
}