---
id: CVE-2026-114646
title: >-
  NoSQL command injection via mismatched raw BSON length prefix written verbatim
  to the wire
summary: >-
  A data-validation flaw exists in the BSON handling and binary serialization
  path of the MongoDB C# Driver. When an application constructs a raw or lazy
  BSON document object from externally supplied binary data, the driver does not
  verify…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'
cvssSource: cna
cwe:
  - CWE-130
vendor: MongoDB
product: C# Driver
affected:
  - c_driver >= 2.0.0 < 3.13.0
published: '2026-10-22'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T21:25:32.332Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-114646'
references:
  - url: 'https://jira.mongodb.org/browse/CSHARP-6157'
  - url: 'https://github.com/mongodb/mongo-csharp-driver/releases/tag/v3.13.0'
  - url: >-
      https://github.com/mongodb/mongo-csharp-driver/security/advisories/GHSA-5chr-phc4-wcj2
tags:
  - cve.org
ingestedAt: '2026-10-22T22:00:50.446Z'
---

## Overview

A data-validation flaw exists in the BSON handling and binary serialization path of the MongoDB C# Driver. When an application constructs a raw or lazy BSON document object from externally supplied binary data, the driver does not verify that the size quantity declared inside that data matches the amount of data actually provided, and it copies the data onto the wire unchanged. An unauthenticated party who can supply binary content to such an application can thereby cause additional elements to be inserted into, or existing elements to be removed from, the database command the application issues, without needing any database credentials of their own. This can result in unauthorized modification of stored data and disclosure of data outside the intended scope of the application's request, bounded by the database privileges the application itself holds.

## Affected

- `c_driver >= 2.0.0 < 3.13.0`

## Remediation

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