CVE-2021-40830
HIGHCVE-2021-40830 is a high-severity (CVSS 8.8) CWE-295 vulnerability in software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk. O3 Security confirms whether CVE-2021-40830 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Improper certificate management in AWS IoT Device SDK v2
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2021-40830 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 365,017 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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 | 1.5.0 |
| 📦npm | aws-iot-device-sdk-v2 | all versions | 1.5.3 |
| 🐍PyPI | awsiotsdk | all versions | 1.6.1 |
Detection & 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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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.
How O3 protects you
O3 pinpoints whether CVE-2021-40830 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2021-40830. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-40830 in your dependencies?
O3 detects CVE-2021-40830 across Maven, npm, PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.