---
id: CVE-2026-18703
title: >-
  An issue in MongoDB Server could allow a party with a valid client certificate
  and a corresponding user account to authenticate using a certificate-based
  authentication method, even when an administrator has configured the server to
  rest…
summary: >-
  An issue in MongoDB Server could allow a party with a valid client certificate
  and a corresponding user account to authenticate using a certificate-based
  authentication method, even when an administrator has configured the server to
  rest…
severity: medium
cvss: 4.2
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N'
cwe:
  - CWE-863
vendor: mongodb
product: mongodb
affected:
  - 'mongodb >= 8.2.0, <= 8.2.12'
  - 'mongodb >= 8.3.0, < 8.3.8'
  - mongodb = 9.0.0
  - mongodb = 9.1.0
patched:
  - mongodb 8.3.8
published: '2026-08-11'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T15:19:02.303'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-18703'
references:
  - url: 'https://jira.mongodb.org/browse/SERVER-127863'
    label: cna@mongodb.com
tags:
  - nvd
epss: 0.00144
epssPercentile: 0.03072
ingestedAt: '2026-08-29T19:41:16.000Z'
---

## Overview

An issue in MongoDB Server could allow a party with a valid client certificate and a corresponding user account to authenticate using a certificate-based authentication method, even when an administrator has configured the server to restrict authentication to other mechanisms. This could allow authentication through a method the administrator intended to disable.

## Affected

- `mongodb >= 8.2.0, <= 8.2.12`
- `mongodb >= 8.3.0, < 8.3.8`
- `mongodb = 9.0.0`
- `mongodb = 9.1.0`

## Remediation

Upgrade past the affected range:

- `mongodb 8.3.8`