---
id: CVE-2026-106434
title: >-
  The explicit decryption component of MongoDB libmongocrypt can return an
  unrecognized encrypted payload unchanged instead of returning a decryption
  error
summary: >-
  The explicit decryption component of MongoDB libmongocrypt can return an
  unrecognized encrypted payload unchanged instead of returning a decryption
  error. An actor who can modify stored encrypted fields, such as a database
  writer, server…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-354
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-2026-106434'
references:
  - url: 'https://jira.mongodb.org/browse/MONGOCRYPT-966'
    label: cna@mongodb.com
tags:
  - nvd
ingestedAt: '2026-10-08T20:06:22.183Z'
---

## Overview

The explicit decryption component of MongoDB libmongocrypt can return an unrecognized encrypted payload unchanged instead of returning a decryption error. An actor who can modify stored encrypted fields, such as a database writer, server, or network intermediary, can cause an affected application to process the supplied bytes as decrypted plaintext.

## Remediation

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