---
id: "GHSA-g7vp-3rxx-v25r"
kind: "vulnerability"
aliases: ["GHSA-g7vp-3rxx-v25r"]
title: "CVE-2026-92943 - Improper validation of certificate with host mismatch in AWS IoT Device SDK for Python"
severity: "high"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["aws", "aws-iot", "aws-iot-device-sdk", "embedded", "iot", "lab-disclosure", "package", "python"]
not_affected_if: ["port-443-alpn-path", "sdk-version-outside-range"]
published_at: "2026-09-17T00:00:00+00:00"
first_seen_at: "2026-10-24T19:43:42+00:00"
updated_at: "2026-10-25T05:30:26+00:00"
sources: [{"source": "lab", "url": "https://aws.amazon.com/security/security-bulletins/rss/2026-114-aws/", "first_seen_at": "2026-10-24T19:43:42+00:00"}]
---

# CVE-2026-92943 - Improper validation of certificate with host mismatch in AWS IoT Device SDK for Python

The AWS IoT Device SDK for Python did not verify that the server certificate matched the AWS IoT Core hostname in its MQTT TLS connection. An attacker positioned on the network can present a certificate for another hostname signed by any trusted CA, read device telemetry and inject MQTT messages the device treats as genuine.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed version with `pip show AWSIoTPythonSDK` and confirm whether it falls in `>=1.5.3` and `<=1.6.0` on Python 3.7 or later.
- Find the SDK in requirements files, lockfiles and forked or vendored copies of the code.

## Fix

- Upgrade AWSIoTPythonSDK to `1.6.1` or later.
- Patch any forked or derivative copies of the SDK with the same fix.
- No workaround exists according to the bulletin.

## Timeline

- 2026-10-24T19:43:42+00:00 lab https://aws.amazon.com/security/security-bulletins/rss/2026-114-aws/ — AWS: CVE-2026-92943 - Improper validation of certificate with host mismatch in AWS IoT Device SDK for Python

## Documents

- [advisory] AWS: CVE-2026-92943 - Improper validation of certificate with host mismatch in AWS IoT Device SDK for Python https://aws.amazon.com/security/security-bulletins/rss/2026-114-aws/

## From the sources

CVE-2026-92943 - Improper validation of certificate with host mismatch in AWS IoT Device SDK for Python

### CVE-2026-92943 - Improper validation of certificate with host mismatch in AWS IoT Device SDK for Python

Bulletin ID: 2026-114-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 09/17/2026 12:00 PM PDT

Description:

AWS IoT Device SDK for Python (AWSIoTPythonSDK) is an open source SDK that lets IoT devices and gateways connect to AWS IoT Core over MQTT. We identified CVE-2026-92943 in the MQTT client TLS connection layer, where the client did not validate that the server certificate matched the AWS IoT Core endpoint hostname. On Python 3.7 and later, an adversary-in-the-middle positioned on the network could present a certificate issued for an unrelated hostname by any certificate authority in the device trust store, impersonate the AWS IoT Core endpoint, read device telemetry, and inject arbitrary MQTT messages that the device processes as authentic. Both SDK default connection paths were affected: X.509 mutual authentication on port 8883 and WebSocket with SigV4 on port 443. The port 443 ALPN path was not affected.

Impacted versions: >=1.5.3 AND <=1.6.0 (on Python 3.7 and later)

Resolution:

This issue has been addressed in AWSIoTPythonSDK version 1.6.1. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.

Workarounds:

There is no workaround. The affected connection paths are the SDK's documented defaults. Customers must upgrade to version 1.6.1.

References:

- CVE-2026-92943
- GHSA-g7vp-3rxx-v25r

Acknowledgement:

We would like to thank George Chen for collaborating on this issue through the coordinated vulnerability disclosure process.

 Please email aws-security@amazon.com with any security questions or concerns.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_