How severe is CVE-2021-40829?

CVE-2021-40829 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-40829?

CVE-2021-40829 affects the following packages: software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk (Maven), aws-iot-device-sdk-v2 (npm), awsiotsdk (PyPI). Ecosystems affected: Maven, npm, PyPI.

How do I fix CVE-2021-40829?

Update software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk to 1.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-40829 is resolved across your whole dependency graph.

How do I detect CVE-2021-40829 in my Maven, npm, PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-40829 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2021-40829 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-40829 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-40829?

CVE-2021-40829 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 30th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-40829?

CVE-2021-40829 is classified as CWE-295 (CWE-295). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-40829 published, and has it been updated?

CVE-2021-40829 was published on November 23, 2021 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven📦 npm🐍 PyPI

Not in CISA KEV

HIGH severity

CVE-2021-40829 — aws-iot-device-sdk

HIGH

CVE-2021-40829 is a high-severity (CVSS 8.8) CWE-295 vulnerability in software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk. A fix is available for software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk — see the affected versions and patch details below.

Improper certificate management in AWS IoT Device SDK v2

Also known asGHSA-743r-5g92-5vgfPYSEC-2021-862

Published

Nov 23, 2021

Updated

Jul 9, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Oct 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs30th percentile — riskier than 30% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-40829 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

3 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

51other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

aws-iot-device-sdk-v2npm

139Kdownloads / week

Description

Connections initialized by the AWS IoT Device SDK v2 for Java (versions prior to 1.4.2), Python (versions prior to 1.6.1), C++ (versions prior to 1.12.7) and Node.js (versions prior to 1.5.3) did not verify server certificate hostname during TLS handshake when overriding Certificate Authorities (CA) in their trust stores on MacOS. This issue has been addressed in aws-c-io submodule versions 0.10.5 onward. This issue affects: Amazon Web Services AWS IoT Device SDK v2 for Java versions prior to 1.4.2 on macOS. Amazon Web Services AWS IoT Device SDK v2 for Python versions prior to 1.6.1 on macOS. Amazon Web Services AWS IoT Device SDK v2 for C++ versions prior to 1.12.7 on macOS. Amazon Web Services AWS IoT Device SDK v2 for Node.js versions prior to 1.5.3 on macOS. Amazon Web Services AWS-C-IO 0.10.4 on macOS.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk`	all versions	1.4.2`software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk:1.4.2`
📦npm	`aws-iot-device-sdk-v2`	all versions	1.5.3`npm install aws-iot-device-sdk-v2@1.5.3`
🐍PyPI	`awsiotsdk`	all versions	1.6.1`pip install --upgrade 'awsiotsdk==1.6.1'`

Affected Products

1 product · 4 configurations

Application

amazon web services internet of things device software development kit v2amazon

< 1.12.7

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk to 1.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-40829 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-40829 in your dependencies?

Find it across Maven, npm, PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

8.8/10CVSS v3 base

Vector breakdown

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Raw vector

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

CWE Classification

CWE-295CWE-295

Weaponization

No known public exploit tooling found.

Timeline

Disclosed

Nov 23, 2021

Last updated

Jul 9, 2026

Identifiers

CVE-2021-40829

GHSA-743r-5g92-5vgf

PYSEC-2021-862

References

Advisorynvd.nist.gov Advisorygithub.com Webgithub.com Webgithub.com Webgithub.com Webgithub.com Packagegithub.com Packagegithub.com Packagegithub.com Packagegithub.com

Related vulnerabilities

Also affects aws-iot-device-sdk

This CVE is high severity; 2 of 3 other CVEs affecting aws-iot-device-sdk are rated as high or higher (top: high).

CVE-2021-40828CVE-2021-40830CVE-2021-40831

Same weakness: CWE-295

This CVE is high severity; 2 of 5 other CVEs with CWE-295 are rated as high or higher (top: critical).

CVE-2026-63374CVE-2026-81868CVE-2026-81871GHSA-6hxq-p678-4hr2CVE-2026-55215Browse all CWE-295

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedJul 9, 2026

CVE-2021-40829 — aws-iot-device-sdk

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2021-40829 in your dependencies?