---
id: CVE-2026-120956
title: remote abort and memory disclosure from a malformed cursor.ns
summary: >-
  The MongoDB C Driver does not validate the type or format of a namespace field
  returned by the server in a query response. A MongoDB endpoint that a client
  application connects to, without needing any credentials, can return a
  malformed …
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-617
vendor: MongoDB
product: C Driver
affected:
  - c_driver >= 1.25.0 <= 1.30.14
  - c_driver >= 2.0.0 <= 2.5.7
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-03T20:01:40.053743Z'
published: '2026-11-03'
updated: '2026-11-03'
sourceUpdated: '2026-11-03T20:01:51.405Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-120956'
references:
  - url: 'https://jira.mongodb.org/browse/CDRIVER-6501'
tags:
  - cve.org
epss: 0.00252
epssPercentile: 0.16809
ingestedAt: '2026-11-05T20:33:06.428Z'
---

## Overview

The MongoDB C Driver does not validate the type or format of a namespace field returned by the server in a query response. A MongoDB endpoint that a client application connects to, without needing any credentials, can return a malformed value in that field. This causes the client application process to terminate, and can also cause the driver to read memory outside an allocated buffer and to send a small amount of the application's own uninitialized heap memory back to the endpoint in a follow-up command. The impact is limited to the process that embeds the driver.

## Affected

- `c_driver >= 1.25.0 <= 1.30.14`
- `c_driver >= 2.0.0 <= 2.5.7`

## Remediation

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