---
id: CVE-2026-106435
title: >-
  The MongoDB Python Driver's binary accelerator can read outside a buffer when
  an application decodes malformed BSON containing a truncated
  regular-expression element without a trailing NUL byte
summary: >-
  The MongoDB Python Driver's binary accelerator can read outside a buffer when
  an application decodes malformed BSON containing a truncated
  regular-expression element without a trailing NUL byte. An actor who can
  supply BSON to the docume…
severity: medium
cvss: 5.1
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-125
published: '2026-10-08'
updated: '2026-10-09'
sourceUpdated: '2026-10-09T12:17:07.723'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-106435'
references:
  - url: 'https://jira.mongodb.org/browse/PYTHON-6110'
    label: cna@mongodb.com
tags:
  - nvd
ingestedAt: '2026-10-08T22:11:53.856Z'
---

## Overview

The MongoDB Python Driver's binary accelerator can read outside a buffer when an application decodes malformed BSON containing a truncated regular-expression element without a trailing NUL byte. An actor who can supply BSON to the documented decode or decode_all API can cause the application process to terminate when the C extension is loaded. The driver's normal database wire-protocol path does not reach this code.

## Remediation

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