{"id":"CVE-2026-81521","summary":"Cross-database write retargeting via unvalidated dotted database name in Client.BulkWrite in the MongoDB Go Driver","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.","modified":"2026-10-01T17:41:49.254294424Z","published":"2026-08-27T18:31:45.450Z","related":["SUSE-SU-2026:4408-1","openSUSE-SU-2026:11803-1"],"database_specific":{"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"}],"cna_assigner":"mongodb"},"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mongodb/mongo-go-driver","events":[{"introduced":"5afecc5d27e39384dd89ccacde921025cb74d7f1"},{"fixed":"1af6d00dbeb70805a69cc9f8fc0828e1f4cef1ee"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:mongodb:go_driver:*:*:*:*:*:mongodb:*:*","extracted_events":[{"introduced":"2.1.0"},{"fixed":"2.8.2"}]}}],"versions":["v2.8.1","v2.8.0","v2.6.0","v2.5.0","v2.4.0","v2.3.0","v2.2.0","v2.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-81521.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","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"}]}