---
id: CVE-2026-114653
title: >-
  Silent client-side encryption bypass via unescaped field-name regex in CSFLE
  schema builder
summary: >-
  A client-side encryption schema construction component in the MongoDB C#
  Driver places caller-supplied field identifiers into a position that is
  interpreted as a pattern expression, without normalizing or validating them.
  As a result, an…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-185
vendor: MongoDB
product: C# Driver
affected:
  - c_driver >= 3.5.0 < 3.13.0
published: '2026-10-22'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T21:25:36.721Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-114653'
references:
  - url: 'https://jira.mongodb.org/browse/CSHARP-6174'
  - url: 'https://github.com/mongodb/mongo-csharp-driver/releases/tag/v3.13.0'
  - url: >-
      https://github.com/mongodb/mongo-csharp-driver/security/advisories/GHSA-ggmm-wc43-vphh
tags:
  - cve.org
ingestedAt: '2026-10-22T22:00:50.447Z'
---

## Overview

A client-side encryption schema construction component in the MongoDB C# Driver places caller-supplied field identifiers into a position that is interpreted as a pattern expression, without normalizing or validating them. As a result, an application that designates certain fields for client-side field-level encryption may have the protection silently fail to apply, so data intended to be encrypted is stored and returned in cleartext; conversely, the rule may apply more broadly than intended. No user action is required to cause the condition, and any party with ordinary read access to the stored data — without possession of the encryption keys — can observe the unprotected values.

## Affected

- `c_driver >= 3.5.0 < 3.13.0`

## Remediation

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