Summary
Improper certificate management in AWS IoT Device SDK v2
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 macOS systems. Additionally, SNI validation is also not enabled when the CA has been "overridden". 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 address this behavior. This issue affects: Amazon Web Services AWS IoT Device SDK v2 for Java versions prior to 1.5.0 on macOS. Amazon Web Services AWS IoT Device SDK v2 for Python versions prior to 1.7.0 on macOS. Amazon Web Services AWS IoT Device SDK v2 for C++ versions prior to 1.14.0 on macOS. Amazon Web Services AWS IoT Device SDK v2 for Node.js versions prior to 1.6.0 on macOS. Amazon Web Services AWS-C-IO 0.10.7 on macOS.
Impact
CVE-2021-40831 has a CVSS score of 6.3 (High). The vector is reachable from an adjacent network, high privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.5.0, 1.6.0, 1.7.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk to 1.5.0 or later; aws-iot-device-sdk-v2 to 1.6.0 or later; awsiotsdk to 1.7.0 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2021-40831? CVE-2021-40831 is a high-severity security vulnerability in software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk (maven), affecting versions < 1.5.0. It is fixed in 1.5.0, 1.6.0, 1.7.0.
- How severe is CVE-2021-40831? CVE-2021-40831 has a CVSS score of 6.3 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2021-40831?
software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk(maven) (versions < 1.5.0)aws-iot-device-sdk-v2(npm) (versions < 1.6.0)awsiotsdk(pip) (versions < 1.7.0)
- Is there a fix for CVE-2021-40831? Yes. CVE-2021-40831 is fixed in 1.5.0, 1.6.0, 1.7.0. Upgrade to this version or later.
- Is CVE-2021-40831 exploitable, and should I be worried? Whether CVE-2021-40831 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2021-40831 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2021-40831?
- Upgrade
software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdkto 1.5.0 or later - Upgrade
aws-iot-device-sdk-v2to 1.6.0 or later - Upgrade
awsiotsdkto 1.7.0 or later
- Upgrade