---
id: CVE-2026-81521
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
summary: >-
  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. A…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-99
  - CWE-791
vendor: mongodb
product: go_driver
affected:
  - 'go_driver >= 2.1.0, < 2.8.2'
patched:
  - go_driver 2.8.2
published: '2026-08-27'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T19:18:15.990'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81521'
references:
  - url: 'https://jira.mongodb.org/browse/GODRIVER-4075'
    label: cna@mongodb.com
  - url: 'https://pkg.go.dev/go.mongodb.org/mongo-driver/v2@v2.8.2'
    label: cna@mongodb.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81521.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-81521'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2525215'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-81521'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81521'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68334'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68044'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68253'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68006'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68254'
  - url: 'https://access.redhat.com/errata/RHSA-2026:84734'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00236
epssPercentile: 0.14462
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-08-28T15:52:01.062590Z'
scores:
  nvd: 6.5
  vendor: 7.5
  cna: 6.5
ingestedAt: '2026-09-29T19:44:04.116Z'
---

## Overview

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

- `go_driver >= 2.1.0, < 2.8.2`

## Remediation

Upgrade past the affected range:

- `go_driver 2.8.2`

## Vendor advisories

- **RHSA-2026:68334** · Red Hat · fixed in: RHEM 1.1 for RHEL 10, RHEM 1.1 for RHEL 9 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68334)
- **RHSA-2026:68044** · Red Hat · fixed in: Red Hat Edge Manager 1.1 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68044)
- **RHSA-2026:68253** · Red Hat · fixed in: Red Hat Edge Manager 1.1 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68253)
- **RHSA-2026:68006** · Red Hat · fixed in: Red Hat Edge Manager 1.2 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68006)
- **RHSA-2026:68254** · Red Hat · fixed in: Red Hat Edge Manager 1.2 · released 2026-09-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:68254)
- **Red Hat VEX** · Important · affected: OpenShift Pipelines, Red Hat OpenShift Dev Spaces, Red Hat OpenShift GitOps, Red Hat Trusted Artifact Signer · no fix planned: OpenShift Pipelines, Red Hat OpenShift GitOps, Red Hat Trusted Artifact Signer, Red Hat OpenShift Dev Spaces · updated 2026-10-19 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81521.json)
- **RHSA-2026:84734** · Red Hat · fixed in: Red Hat OpenShift AI 3.4 · released 2026-10-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:84734)