{"id":"CVE-2026-81521","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-81521","generatedAt":"2026-10-28T02:17:39.768Z","title":"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.","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.","published":"2026-08-27T20:18:50.000Z","lastModified":"2026-10-06T19:18:16.000Z","status":"Analyzed","sourceIdentifier":"cna@mongodb.com","cvss":{"version":"4.0","score":7.1,"severity":"HIGH","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-99"],"affected":["mongodb/go driver"],"epss":{"score":0.00236,"percentile":0.14407,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.24%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://jira.mongodb.org/browse/GODRIVER-4075","tags":["Vendor Advisory"],"source":"cna@mongodb.com"},{"url":"https://pkg.go.dev/go.mongodb.org/mongo-driver/v2@v2.8.2","tags":["Product"],"source":"cna@mongodb.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-81521","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}