Vulnerability from bitnami_vulndb
Published
2026-08-25 11:42
Modified
2026-10-07 12:12
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.

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "keycloak",
        "purl": "pkg:bitnami/keycloak"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "26.2.0"
            },
            {
              "fixed": "26.2.1"
            },
            {
              "introduced": "26.2.15"
            },
            {
              "fixed": "26.3.0"
            },
            {
              "introduced": "26.4.0"
            },
            {
              "fixed": "26.4.1"
            },
            {
              "introduced": "26.4.11"
            },
            {
              "fixed": "26.5.0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-4634"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:text-only:*:*:*",
      "cpe:2.3:a:keycloak:keycloak:*:*:*:*:*:*:*:*"
    ],
    "severity": "High"
  },
  "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.",
  "id": "BIT-keycloak-2026-4634",
  "modified": "2026-10-07T12:12:41.058Z",
  "published": "2026-08-25T11:42:30.857Z",
  "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"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:76132"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:76134"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:76128"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:76129"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:76130"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "Keycloak: keycloak: denial of service via excessive processing of openid connect scope parameters"
}



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