KMS master key exposure via unredacted credential serialization in driver settings string

{
  "id": "f9e1f4004fb7ac72936c4015d7eb9694e2449bb242044d4c90378ae0e0d06b46",
  "url": "https://osv.dev/vulnerability/CVE-2026-81530",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "KMS master key exposure via unredacted credential serialization in driver settings string",
    "summary": "A weakness in the client-side encryption configuration surface of the MongoDB C# Driver causes sensitive key-management credential material supplied by the application to be reproduced verbatim in the driver's human-readable diagnostic representation of its client settings, instead of being masked as other secret fields are. A party able to read the application's logs, diagnostic output, or a process memory dump may thereby recover the plaintext credentials and use them to decrypt protected field data.",
    "evidence": "osv:CVE-2026-81530",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-81530",
      "aliases": [
        "CVE-2026-81530"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mongodb/mongo-csharp-driver",
              "type": "GIT",
              "events": [
                {
                  "introduced": "569905ff5e778c38ea19d9d0392496a83e1704ed"
                },
                {
                  "fixed": "682ad0faea0a03648ee2c4ca8f48c3b04f4c9ab8"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:mongodb:c\\#_driver:*:*:*:*:*:mongodb:*:*",
                    "range": [
                      {
                        "introduced": "2.10.0"
                      },
                      {
                        "fixed": "3.11.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.11.0",
            "v3.10.0",
            "v3.9.0",
            "v3.8.0",
            "v3.7.1",
            "v3.7.0",
            "v3.6.0",
            "v3.5.0",
            "v3.4.0",
            "v3.3.0",
            "v3.2.1",
            "v3.2.0",
            "v3.1.0",
            "v3.0.0",
            "v2.28.0",
            "v2.27.0",
            "v2.26.0",
            "v2.25.0",
            "v2.24.0",
            "v2.23.1",
            "v2.23.0",
            "v2.22.0",
            "v2.21.0",
            "v2.20.0",
            "v2.19.0",
            "v2.18.0",
            "v2.17.0",
            "v2.16.0",
            "v2.15.0",
            "v2.14.0",
            "v2.14.0-beta1",
            "v2.13.0",
            "v2.13.0-beta1",
            "v2.12.0",
            "v2.12.0-beta1",
            "v2.11.0",
            "v2.11.0-beta2",
            "v2.11.0-beta1",
            "v2.10.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-81530.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:21.413984090Z",
      "provider": "osv",
      "references": [
        "https://jira.mongodb.org/browse/CSHARP-6164",
        "https://www.nuget.org/packages/MongoDB.Driver/3.11.1",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81530.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-81530"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-532"
        ],
        "cna_assigner": "mongodb",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "2.10.0"
                  },
                  {
                    "fixed": "3.11.1"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81530.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-81530",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 487795,
  "published_at": "2026-08-27T18:32:32.877+00:00"
}