Org.keycloak/keycloak-quarkus-server: keycloak: unauthorized access via jwt authorization grant with disabled users

{
  "id": "8fe36648a36e134c0e8becb961e2b6b582bf874495180ef70f1c100cfff4ba64",
  "url": "https://osv.dev/vulnerability/CVE-2026-1609",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Org.keycloak/keycloak-quarkus-server: keycloak: unauthorized access via jwt authorization grant with disabled users",
    "summary": "A flaw was found in Keycloak. When the JSON Web Token (JWT) authorization grant preview feature is enabled and a user account is disabled, Keycloak fails to validate the user’s disabled status during JWT authorization grant processing. A remote attacker with low privileges can exploit this improper access control vulnerability by presenting a valid assertion token from an external identity provider to obtain a JWT for a disabled user. This allows unauthorized access to sensitive resources.",
    "evidence": "osv:CVE-2026-1609",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-1609",
      "aliases": [
        "BIT-keycloak-2026-1609",
        "CVE-2026-1609"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/keycloak/keycloak",
              "type": "GIT",
              "events": [
                {
                  "introduced": "4c5b05789e16ec963e9477ce1f58118ca89c4d6e"
                },
                {
                  "last_affected": "4c5b05789e16ec963e9477ce1f58118ca89c4d6e"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:redhat:build_of_keycloak:26.5.2:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "26.5.2"
                      },
                      {
                        "last_affected": "26.5.2"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "26.5.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-1609.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:43.222976688Z",
      "provider": "osv",
      "references": [
        "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
        "https://github.com/keycloak/keycloak/releases/tag/26.5.3",
        "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-1609.json",
        "https://access.redhat.com/security/cve/CVE-2026-1609",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/1xxx/CVE-2026-1609.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-1609",
        "https://bugzilla.redhat.com/show_bug.cgi?id=2435257",
        "https://github.com/keycloak/keycloak/issues/46144"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-284"
        ],
        "cna_assigner": "redhat",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "26.5.0"
                  },
                  {
                    "fixed": "26.5.3"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/1xxx/CVE-2026-1609.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-1609",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 510891,
  "published_at": "2026-07-16T00:26:10.772+00:00"
}