{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:mongodb:go_driver:*:*:*:*:*:mongodb:*:*",
            "extracted_events": [
              {
                "introduced": "2.1.0"
              },
              {
                "fixed": "2.8.2"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "5afecc5d27e39384dd89ccacde921025cb74d7f1"
            },
            {
              "fixed": "1af6d00dbeb70805a69cc9f8fc0828e1f4cef1ee"
            }
          ],
          "repo": "https://github.com/mongodb/mongo-go-driver",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "mongodb",
    "cwe_ids": [
      "CWE-99"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81521.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "2.1.0"
          },
          {
            "fixed": "2.8.2"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "The MongoDB Go Driver's client-level bulk write operation may accept a caller-supplied database name containing a reserved separator character without escaping it before the name is used to build the target namespace for the operation. An application that passes untrusted input as a database name could therefore have the write directed at a database and collection other than the ones it intended. Only the Client.BulkWrite API is affected.",
  "id": "CVE-2026-81521",
  "modified": "2026-10-01T03:30:54.483645322Z",
  "published": "2026-08-27T18:31:45.450Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://jira.mongodb.org/browse/GODRIVER-4075"
    },
    {
      "type": "WEB",
      "url": "https://pkg.go.dev/go.mongodb.org/mongo-driver/v2@v2.8.2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81521.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-81521"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Cross-database write retargeting via unvalidated dotted database name in Client.BulkWrite in the MongoDB Go Driver"
}