---
id: CVE-2026-92943
title: >-
  Improper validation of certificate with host mismatch in the MQTT client TLS
  connection layer in AWS IoT Device SDK for Python 1.5.3 through 1.6.0 on
  Python 3.7 and later might allow an adversary-in-the-middle actor to
  impersonate the AW…
summary: >-
  Improper validation of certificate with host mismatch in the MQTT client TLS
  connection layer in AWS IoT Device SDK for Python 1.5.3 through 1.6.0 on
  Python 3.7 and later might allow an adversary-in-the-middle actor to
  impersonate the AW…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-297
vendor: AWS
product: AWSIoTPythonSDK
affected:
  - AWSIoTPythonSDK >= 1.5.3 <= 1.6.0
published: '2026-09-17'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T17:48:19.003'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92943'
references:
  - url: 'https://aws.amazon.com/security/security-bulletins/2026-114-aws/'
    label: ff89ba41-3aa1-4d27-914a-91399e9639e5
  - url: 'https://github.com/aws/aws-iot-device-sdk-python/releases/tag/v1.6.1'
    label: ff89ba41-3aa1-4d27-914a-91399e9639e5
  - url: >-
      https://github.com/aws/aws-iot-device-sdk-python/security/advisories/GHSA-g7vp-3rxx-v25r
    label: ff89ba41-3aa1-4d27-914a-91399e9639e5
  - url: 'https://pypi.org/project/AWSIoTPythonSDK/1.6.1/'
    label: ff89ba41-3aa1-4d27-914a-91399e9639e5
tags:
  - nvd
  - cve.org
epss: 0.00381
epssPercentile: 0.2936
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-17T19:56:30.974492Z'
ingestedAt: '2026-09-17T19:26:25.322Z'
---

## Overview

Improper validation of certificate with host mismatch in the MQTT client TLS connection layer in AWS IoT Device SDK for Python 1.5.3 through 1.6.0 on Python 3.7 and later might allow an adversary-in-the-middle actor to impersonate the AWS IoT Core endpoint, read device telemetry, and inject arbitrary MQTT messages that the device processes as authentic, via a certificate issued for an unrelated hostname by a certificate authority present in the device trust store.



To remediate this issue, users should upgrade to version 1.6.1.

## Remediation

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