---
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
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-106434.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-106434'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-106434'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
ingestedAt: '2026-10-08T20:06:22.183Z'
vendor: Red Hat
epss: 0.00112
epssPercentile: 0.01371
product: libmongocrypt
affected:
  - libmongocrypt >= 1.5.0 < 1.20.5
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-08T19:30:38.647440Z'
---

## 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.

## Vendor advisories

- **Red Hat VEX** · updated 2026-10-09 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-106434.json)