Doorkeeper OpenID Connect: DCR endpoint persists unvalidated client-supplied scopes

{
  "id": "2564faa62688748c6ec83c93fc3eaa154d1070da51628640a6e1b80edc1adc61",
  "url": "https://osv.dev/vulnerability/CVE-2026-70665",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Doorkeeper OpenID Connect: DCR endpoint persists unvalidated client-supplied scopes",
    "summary": "Doorkeeper OpenID Connect implements an OpenID Connect authentication provider for Rails applications on top of Doorkeeper. Prior to 1.10.4, the Dynamic Client Registration (DCR) endpoint persists client-supplied scopes without validating them against the server's configured scope set. Under certain conditions, this allows a self-registered client to obtain scopes beyond what the server intended to grant. In DynamicClientRegistrationController#application_params, the scopes attribute is assigned directly from params[:scope] with no validation against Doorkeeper.configuration.scopes or optional_scopes. Combined with enforce_configured_scopes being off by default and Doorkeeper's ScopeChecker prioritizing application-level scopes over server-level scopes, this creates a privilege escalation path. This issue is fixed in version 1.10.4.",
    "evidence": "osv:CVE-2026-70665",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-70665",
      "aliases": [
        "CVE-2026-70665",
        "GHSA-8r7r-wh7x-27ff"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/doorkeeper-gem/doorkeeper-openid_connect",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "9f956e5012b36f593e99803680ed4761340f89a5"
                },
                {
                  "fixed": "24c3cb1729b69f48649a6f4491dcae69f805000d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.10.4"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "24c3cb1729b69f48649a6f4491dcae69f805000d"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.10.3",
            "v1.10.2",
            "v1.10.1",
            "v1.10.0",
            "v1.9.0",
            "v1.8.11",
            "v1.8.10",
            "v.1.8.9",
            "v1.8.8",
            "v1.8.7",
            "v1.8.6",
            "v1.8.5",
            "v1.8.4",
            "v1.8.3",
            "v1.8.2",
            "v1.8.1",
            "v1.8.0",
            "v1.8.0.pre.rc1",
            "v1.7.5",
            "v1.7.4",
            "v1.7.3",
            "v1.7.2",
            "v1.7.1",
            "v1.7.0",
            "v1.6.3",
            "v1.6.2",
            "v1.6.1",
            "v1.6.0",
            "v1.5.5",
            "v1.5.4",
            "v1.5.3",
            "v1.5.2",
            "v1.5.1",
            "v1.5.0",
            "v1.4.0",
            "v1.3.0",
            "v1.2.0",
            "v1.1.2",
            "v1.1.1",
            "v1.1.0",
            "v1.0.1",
            "v1.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-70665.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.148813446Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/70xxx/CVE-2026-70665.json",
        "https://github.com/doorkeeper-gem/doorkeeper-openid_connect/security/advisories/GHSA-8r7r-wh7x-27ff",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-70665",
        "https://github.com/doorkeeper-gem/doorkeeper-openid_connect/commit/24c3cb1729b69f48649a6f4491dcae69f805000d"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-285"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/70xxx/CVE-2026-70665.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-70665",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 499093,
  "published_at": "2026-08-25T22:09:53.197+00:00"
}