---
id: CVE-2026-81522
title: >-
  A weakness in the MongoDB C++ Driver's handling of caller-supplied namespace
  identifiers allows special characters embedded in those identifiers
summary: >-
  A weakness in the MongoDB C++ Driver's handling of caller-supplied namespace
  identifiers allows special characters embedded in those identifiers. An
  application that builds a namespace identifier from untrusted input without
  validating i…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-116
published: '2026-08-27'
updated: '2026-08-29'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81522'
references:
  - url: 'https://github.com/mongodb/mongo-cxx-driver/releases/tag/r4.5.1'
    label: cna@mongodb.com
  - url: 'https://jira.mongodb.org/browse/CXX-3552'
    label: cna@mongodb.com
tags:
  - nvd
epss: 0.00265
epssPercentile: 0.1868
ingestedAt: '2026-08-29T21:42:36.301Z'
---

## Overview

A weakness in the MongoDB C++ Driver's handling of caller-supplied namespace identifiers allows special characters embedded in those identifiers. An application that builds a namespace identifier from untrusted input without validating it may therefore have its operation directed at a different target than intended. This can result in limited unauthorized read and write access to data belonging to another logical tenant of the affected application.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.