CVE-2021-40828

TLS hostname validation issues within AWS IoT Device SDKs on Windows

HIGH

8.8

CVSS Score

Published: November 22, 2021 at 11:41 PM UTC

Updated: June 17, 2026 at 04:07 AM UTC

4 products affected across 2 vendorsAmazon Web Services Internet of Things Device Software Development Kit V2Amazon Web Services AWS C IoAWS-C-IO· also runs on 1 platform

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Severity

HIGH8.8

Exploit prediction

EPSS 0.4%

Description

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Amazon Web Services AWS C Io · Amazon

95%

v < 0.9.13

Affected range stops below 0.9.13, so it looks safe — our inference, not a vendor statement

microsoft-windows (environment)

Amazon Web Services Internet of Things Device Software Development Kit V2 · Amazonmaven

95%

v < 1.12.7v < 1.3.3v < 1.5.1v < 1.5.18

Affected range stops below 1.12.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.3.3, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.5.1, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.5.18, so it looks safe — our inference, not a vendor statement

microsoft-windows (environment)

AWS-C-IO · Amazon Web Services

60%

0.9.12

AWS IoT Device SDK v2 · Amazon Web Services

60%

v < 1.12.7v < 1.3.3v < 1.5.18v < 1.5.3

Affected range stops below 1.12.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.3.3, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.5.18, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.5.3, so it looks safe — our inference, not a vendor statement

Runs on — not affected

The affected product only carries this flaw when running on these platforms. The platforms themselves are not vulnerable.

Windows · Microsoft

95%

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (5)

x_refsource_MISCProduct

Source: [email protected]

https://github.com/aws/aws-iot-device-sdk-cpp-v2

x_refsource_MISCProduct

Source: [email protected]

https://github.com/aws/aws-iot-device-sdk-java-v2

x_refsource_MISCProduct

Source: [email protected]

https://github.com/aws/aws-iot-device-sdk-js-v2

x_refsource_MISCProduct

Source: [email protected]

https://github.com/aws/aws-iot-device-sdk-python-v2

x_refsource_MISCProduct

Source: [email protected]

https://github.com/awslabs/aws-c-io/

CVSS

8.8HIGH[email protected]

Attack Vector: ADJACENT_NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: HIGH
Integrity: HIGH
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-295

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