CVE-2021-40830 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
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-40830 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
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.
aws-iot-device-sdk-v2npmDescription
The AWS IoT Device SDK v2 for Java, Python, C++ and Node.js appends a user supplied Certificate Authority (CA) to the root CAs instead of overriding it on Unix systems. TLS handshakes will thus succeed if the peer can be verified either from the user-supplied CA or the system’s default trust-store. Attackers with access to a host’s trust stores or are able to compromise a certificate authority already in the host's trust store (note: the attacker must also be able to spoof DNS in this case) may be able to use this issue to bypass CA pinning. An attacker could then spoof the MQTT broker, and either drop traffic and/or respond with the attacker's data, but they would not be able to forward this data on to the MQTT broker because the attacker would still need the user's private keys to authenticate against the MQTT broker. The 'aws_tls_ctx_options_override_default_trust_store_*' function within the aws-c-io submodule has been updated to override the default trust store. This corrects this issue. This issue affects: Amazon Web Services AWS IoT Device SDK v2 for Java versions prior to 1.5.0 on Linux/Unix. Amazon Web Services AWS IoT Device SDK v2 for Python versions prior to 1.6.1 on Linux/Unix. Amazon Web Services AWS IoT Device SDK v2 for C++ versions prior to 1.12.7 on Linux/Unix. Amazon Web Services AWS IoT Device SDK v2 for Node.js versions prior to 1.5.3 on Linux/Unix. Amazon Web Services AWS-C-IO 0.10.4 on Linux/Unix.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk | all versions | 1.5.0software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk:1.5.0 |
| 📦npm | aws-iot-device-sdk-v2 | all versions | 1.5.3npm install aws-iot-device-sdk-v2@1.5.3 |
| 🐍PyPI | awsiotsdk | all versions | 1.6.1pip install --upgrade 'awsiotsdk==1.6.1' |
Affected Products
amazon web services aws-c-ioamazonamazon web services internet of things device software development kit v2amazonDetection & mitigation playbook
Open-source dependencyDetect
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 1.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-40830 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
Is CVE-2021-40830 in your dependencies?
Find it across Maven, npm, PyPI, including transitive dependencies.