CVE-2021-40828: Amazon Web Services Aws-C-Io

High severity, CVSS 8.8. EPSS: 0.4% chance of exploitation in the next 30 days.

Connections initialized by the AWS IoT Device SDK v2 for Java (versions prior to 1.3.3), Python (versions prior to 1.5.18), C++ (versions prior to 1.12.7) and Node.js (versions prior to 1.5.1) did not verify server certificate hostname during TLS handshake when overriding Certificate Authorities (CA) in their trust stores on Windows. This issue has been addressed in aws-c-io submodule versions 0.9.13 onward. This issue affects: Amazon Web Services AWS IoT Device SDK v2 for Java versions prior to 1.3.3 on Microsoft Windows. Amazon Web Services AWS IoT Device SDK v2 for Python versions prior to 1.5.18 on Microsoft Windows. Amazon Web Services AWS IoT Device SDK v2 for C++ versions prior to 1.12.7 on Microsoft Windows. Amazon Web Services AWS IoT Device SDK v2 for Node.js versions prior to 1.5.3 on Microsoft Windows.

Affected products

• Amazon Amazon Web Services Aws-C-Io: before 0.9.13 (fixed in 0.9.13)
• Amazon Amazon Web Services Internet Of Things Device Software Development Kit v2: before 1.3.3 (fixed in 1.3.3); before 1.5.1 (fixed in 1.5.1); before 1.5.18 (fixed in 1.5.18); before 1.12.7 (fixed in 1.12.7)

Published 2021-11-23. Last modified 2026-06-17.