---
id: CVE-2026-114651
title: >-
  Cross-document data leak via malformed BSON array parsing in reused thread
  buffer
summary: >-
  A memory-handling weakness in the BSON deserialization component of the
  MongoDB C# Driver may cause data left over from previously processed content
  to be returned when specially crafted serialized input is parsed. An
  unauthenticated par…
severity: medium
cvss: 4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-908
vendor: MongoDB
product: C# Driver
affected:
  - c_driver >= 2.26.0 < 3.13.0
published: '2026-10-22'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T20:38:23.091Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-114651'
references:
  - url: 'https://jira.mongodb.org/browse/CSHARP-6170'
  - url: 'https://github.com/mongodb/mongo-csharp-driver/releases/tag/v3.13.0'
  - url: >-
      https://github.com/mongodb/mongo-csharp-driver/security/advisories/GHSA-f8xm-c88f-wq46
tags:
  - cve.org
ingestedAt: '2026-10-22T22:00:50.420Z'
---

## Overview

A memory-handling weakness in the BSON deserialization component of the MongoDB C# Driver may cause data left over from previously processed content to be returned when specially crafted serialized input is parsed. An unauthenticated party able to supply serialized data to an application that maps certain primitive collection types can cause residual bytes from unrelated data processed earlier on the same execution thread to be surfaced as legitimate values. This can result in disclosure of a limited amount of information belonging to other requests or principals of the consuming application. No authentication or special privileges within the application are required.

## Affected

- `c_driver >= 2.26.0 < 3.13.0`

## Remediation

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