---
id: CVE-2026-106433
title: >-
  Improper state management in MongoDB libmongocrypt can cause provider-specific
  data to be treated as an incompatible type when cleaning up a key document
  containing duplicate masterKey fields
summary: >-
  Improper state management in MongoDB libmongocrypt can cause provider-specific
  data to be treated as an incompatible type when cleaning up a key document
  containing duplicate masterKey fields. An authenticated actor who can modify
  key va…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-843
published: '2026-10-08'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T20:49:23.240'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-106433'
references:
  - url: 'https://jira.mongodb.org/browse/MONGOCRYPT-964'
    label: cna@mongodb.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-08T20:06:22.182Z'
epss: 0.00267
epssPercentile: 0.18692
vendor: MongoDB
product: libmongocrypt
affected:
  - libmongocrypt >= 1.1.0 < 1.20.5
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-08T19:30:18.348159Z'
---

## Overview

Improper state management in MongoDB libmongocrypt can cause provider-specific data to be treated as an incompatible type when cleaning up a key document containing duplicate masterKey fields. An authenticated actor who can modify key vault documents, or a server that returns such a key document, can cause invalid memory access and invalid frees in the client process. This can terminate the application or corrupt process memory.

## Remediation

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