{"cve":"CVE-2026-81521","nvd":{"published":"2026-08-27T20:18:50.350","modified":"2026-10-06T19:18:15.990","status":"Analyzed","description":"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.","cvss_v4":{"vector":"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","score":7.1},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","score":6.5},"cwes":["CWE-99"],"references":["https://jira.mongodb.org/browse/GODRIVER-4075","https://pkg.go.dev/go.mongodb.org/mongo-driver/v2@v2.8.2"],"products":["mongodb:go_driver"],"source":"nvd","synced_at":"2026-10-19T22:50:17.453294893+00:00"},"epss":{"cve":"CVE-2026-81521","score":0.00236,"percentile":0.14395,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}