CoreWCF: SAML SubjectConfirmation methods and holder-of-key proof keys are not enforced

{
  "id": "e6aafb2b8f177d10256ffed536e2156e7d3f5303edfc0133aa7cf2c0f4a2f803",
  "url": "https://osv.dev/vulnerability/CVE-2026-54781",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CoreWCF: SAML SubjectConfirmation methods and holder-of-key proof keys are not enforced",
    "summary": "CoreWCF is a port of the service side of Windows Communication Foundation (WCF) to .NET Core. Prior to 1.8.1 and 1.9.1, CoreWCF SAML token validation does not enforce SubjectConfirmation method URIs or holder-of-key proof keys in SamlSecurityTokenHandler, allowing holder-of-key downgrade or custom confirmation method assertions to authenticate a subject without proving authority over the assertion. This issue is fixed in versions 1.8.1 and 1.9.1.",
    "evidence": "osv:CVE-2026-54781",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-54781",
      "aliases": [
        "CVE-2026-54781",
        "GHSA-48pq-2xq3-c2m4"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/corewcf/corewcf",
              "type": "GIT",
              "events": [
                {
                  "introduced": "39b2f02978e497955a560c72b5ccdff5c0dbcda1"
                },
                {
                  "fixed": "1f7a0811da5128db40fd7b868ae0aac0c581f91f"
                },
                {
                  "introduced": "0"
                },
                {
                  "fixed": "7c0920fe16adc497efae82881ac0f1e4d7ac98d0"
                },
                {
                  "fixed": "6a99df3242f54acd6f89edfd6050430b72d0c685"
                },
                {
                  "fixed": "86dd3232b6b8aaf32281be9e8d798afad6145d58"
                },
                {
                  "fixed": "9eb9b46d1c2af06fb71f656a02f4d5b4649c1f03"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "1.9.0"
                      },
                      {
                        "fixed": "1.9.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.8.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "6a99df3242f54acd6f89edfd6050430b72d0c685"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "86dd3232b6b8aaf32281be9e8d798afad6145d58"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "9eb9b46d1c2af06fb71f656a02f4d5b4649c1f03"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "7c0920fe16adc497efae82881ac0f1e4d7ac98d0"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v1.8.1"
                  },
                  {
                    "range": [
                      {
                        "fixed": "1f7a0811da5128db40fd7b868ae0aac0c581f91f"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v1.9.1"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.8.0",
            "v1.9.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54781.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:45.394873953Z",
      "provider": "osv",
      "references": [
        "https://github.com/CoreWCF/CoreWCF/releases/tag/v1.8.1",
        "https://github.com/CoreWCF/CoreWCF/releases/tag/v1.9.1",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54781.json",
        "https://github.com/CoreWCF/CoreWCF/security/advisories/GHSA-48pq-2xq3-c2m4",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-54781",
        "https://github.com/CoreWCF/CoreWCF/commit/6a99df3242f54acd6f89edfd6050430b72d0c685",
        "https://github.com/CoreWCF/CoreWCF/commit/86dd3232b6b8aaf32281be9e8d798afad6145d58",
        "https://github.com/CoreWCF/CoreWCF/commit/9eb9b46d1c2af06fb71f656a02f4d5b4649c1f03"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-287",
          "CWE-345"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54781.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-54781",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 513297,
  "published_at": "2026-07-08T22:19:40.784+00:00"
}