# CVE-2026-81521

## Summary

- **CVE ID:** CVE-2026-81521
- **Severity:** HIGH
- **CVSS Score:** 7.1 (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)
- **CWE:** CWE-99
- **Published:** Aug 27, 2026
- **Last Modified:** Aug 28, 2026

## 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.

## Affected Products

- MongoDB — GO Driver (2.1.0)

## References

- [CNA](https://pkg.go.dev/go.mongodb.org/mongo-driver/v2@v2.8.2)
- [CNA](https://jira.mongodb.org/browse/GODRIVER-4075)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.20%
- **EPSS Percentile:** 10.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._