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Amazon Web Services Aws C IoApplication · Amazon

CVE-2021-40828

HIGH · 8.8 CVSS v3.1 Published 2021-11-23
Fix available
A fix is available. Upgrade to 0.9.13 / 1.3.3 or later.
See remediation →
93/100
Remediation priority · Urgent
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The AWS IoT Device SDK v2 for Java, Python, C++, and Node.js failed to verify server certificate hostname during TLS handshake when overriding Certificate Authorities (CA) in their trust stores on Microsoft Windows. This allows man-in-the-middle attackers to impersonate legitimate IoT servers by presenting a valid certificate for any hostname, bypassing the critical hostname verification step in TLS validation.

MitigationUpgrade AWS IoT Device SDK v2 to patched versions (Java 1.3.3+, Python 1.5.18+, C++ 1.12.7+, Node.js 1.5.1+) or update the aws-c-io submodule to version 0.9.13 or later. This is critical for IoT deployments on Windows.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Amazon Web Services Aws C IoApplication
Affected:< 0.9.13
Amazon Web Services Internet Of Things Device Software Development Kit V2Application
Affected:< 1.3.3< 1.5.1< 1.5.18< 1.12.7

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the AWS IoT Device SDK v2 language in use
    Inspect your project dependencies, package manager files (e.g., package.json for Node.js, requirements.txt for Python, pom.xml for Java), or compiled binaries to determine which AWS IoT Device SDK v2 language binding is deployed
    Affected if Any of Java, Python, C++, or Node.js bindings of AWS IoT Device SDK v2 are in use
  2. Check the installed SDK version against affected ranges
    Run the appropriate command to query the SDK version: pip show aws-iot-device-sdk-python-v2 for Python, npm list aws-iot-device-sdk-v2 for Node.js, or inspect the Maven/Java dependency for Java. For C++, check the linked aws-c-io library version
    Affected if Version is below 1.3.3 (Java), 1.5.1 (Node.js), 1.5.18 (Python), 1.12.7 (C++), or aws-c-io is below 0.9.13
  3. Confirm the deployment platform is Microsoft Windows
    Run 'systeminfo' or check the OS environment variable (echo %OS% or uname -a on WSL) to verify the operating system
    Affected if The application is running on any Microsoft Windows version
  4. Determine if custom CA override is configured
    Search configuration files, environment variables, and application code for calls that override default trust stores, such as AWS_IOT_ROOT_CA_PATH environment variable, custom endpoint configurations, or tls_opts with custom CA settings in the SDK initialization
    Affected if The SDK is configured to use a custom Certificate Authority instead of the default system trust store

You are affected if you are running an AWS IoT Device SDK v2 version below the patched threshold on Windows with custom CA overrides configured, enabling man-in-the-middle attacks due to missing hostname verification

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.9.13 / 1.3.3 / 1.5.1 or later
Fixed in 0.9.131.3.31.5.1
Interim mitigation

Upgrade AWS IoT Device SDK v2 to patched versions (Java 1.3.3+, Python 1.5.18+, C++ 1.12.7+, Node.js 1.5.1+) or update the aws-c-io submodule to version 0.9.13 or later. This is critical for IoT deployments on Windows.

Recommended fix High confidence

aws-c-io 0.9.13 (or language-specific SDK: Java 1.3.3+, Python 1.5.18+, C++ 1.12.7+, Node.js 1.5.1+)

  1. Identify which AWS IoT Device SDK v2 language/framework you are using (Java, Python, C++, or Node.js)
  2. Check your current installed version of the SDK
  3. For Java SDK users: upgrade to version 1.3.3 or later
  4. For Python SDK users: upgrade to version 1.5.18 or later
  5. For C++ SDK users: upgrade to version 1.12.7 or later
  6. For Node.js SDK users: upgrade to version 1.5.1 (or 1.5.3 per description) or later
  7. Alternatively, ensure the aws-c-io submodule is updated to version 0.9.13 or later
  8. After upgrade, verify TLS certificate hostname validation is functioning correctly on Windows

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Amazon Web Services Aws C Io Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-40828 in production — separate from our analysis above.

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What this is

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