---
id: CVE-2026-18693
title: >-
  An issue in MongoDB Server's handling of timeseries collections could allow an
  authenticated user with write privileges to cause an internal data structure
  to become inconsistent through certain document insertions
summary: >-
  An issue in MongoDB Server's handling of timeseries collections could allow an
  authenticated user with write privileges to cause an internal data structure
  to become inconsistent through certain document insertions. A subsequent
  insert i…
severity: high
cvss: 7.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H'
cwe:
  - CWE-787
vendor: mongodb
product: mongodb
affected:
  - 'mongodb >= 7.0.0, < 7.0.40'
  - 'mongodb >= 8.0.0, < 8.0.29'
  - '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: '2026-09-16T15:16:33.437'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-18693'
references:
  - url: 'https://jira.mongodb.org/browse/SERVER-129994'
    label: cna@mongodb.com
tags:
  - nvd
epss: 0.0024
epssPercentile: 0.15358
ingestedAt: '2026-08-29T19:41:15.601Z'
---

## Overview

An issue in MongoDB Server's handling of timeseries collections could allow an authenticated user with write privileges to cause an internal data structure to become inconsistent through certain document insertions. A subsequent insert into the affected bucket could then result in the server accessing memory outside its intended bounds, potentially causing a server crash (denial of service), exposure of limited memory contents, or memory corruption.

## Affected

- `mongodb >= 7.0.0, < 7.0.40`
- `mongodb >= 8.0.0, < 8.0.29`
- `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`