{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "source": "REFERENCES"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "b2aea6146e62e1f292aff2b5ab65086e9c82b1a5"
            }
          ],
          "repo": "https://github.com/eclipse-lyo/lyo",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "eclipse",
    "cwe_ids": [
      "CWE-863"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18918.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "2.0.0"
          },
          {
            "fixed": "7.0.0"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "In Eclipse Lyo versions 2.0.0 to 7.0.0, OAuth server authorization checks can be bypassed when the 2-legged auth is supported by the server. In those cases, application that based their authz filters upon Lyo-provided `AbstractAdapterCredentialsFilter`, are vulnerable. An attacked can create a provisional trusted client (valid use-case) but then it can be used as a trusted client immediately without requiring the administrator approval to clear the provisional status. The 3-legged path requiring user interaction is not vulnerable and rejects provisional clients.",
  "id": "CVE-2026-18918",
  "modified": "2026-09-01T03:30:51.250436144Z",
  "published": "2026-08-28T08:54:07.990Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/eclipse-lyo/lyo/releases/tag/v6.0.1.Final"
    },
    {
      "type": "WEB",
      "url": "https://github.com/eclipse-lyo/lyo/releases/tag/v7.0.0.Beta3"
    },
    {
      "type": "WEB",
      "url": "https://gitlab.eclipse.org/security/cve-assignment/-/work_items/221"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18918.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-18918"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/AU:Y/R:U/V:C/RE:L/U:Red",
      "type": "CVSS_V4"
    }
  ],
  "summary": "OAuth 1.0 session-fixation chain via unauthenticated provisional-consumer registration and insecure v1_0Allowed default"
}