Improper certificate management in AWS IoT Device SDK v2

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.3 · CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2021-40831: 0.64% estimated exploitation activity in the next 30 days; percentile 50.54 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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 awstlsctxoptionsoverridedefaulttruststore function within the aws-c-io…

Published by the source

24 Nov 2021, 20:35 UTC

Last modified by the source

23 Nov 2024, 05:25 UTC

Source last checked

26 Oct 2026, 12:31 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-j3f7-7rmc-6wqj

2. Revision 2 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-j3f7-7rmc-6wqj

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# Patch Next advisory brief: CVE-2021-40831

Advisory: Improper certificate management in AWS IoT Device SDK v2
IDs: CVE-2021-40831, GHSA-j3f7-7rmc-6wqj
Record: https://patchnext.com/advisories/cve-2021-40831 (revision 3, source checked 26 Oct 2026, 12:31 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: awsiotsdk 1.7.0; software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk 1.5.0; aws-iot-device-sdk-v2 1.6.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI awsiotsdk: affected < 1.7.0; fixed in 1.7.0
- Maven software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk: affected < 1.5.0; fixed in 1.5.0
- npm aws-iot-device-sdk-v2: affected < 1.6.0; fixed in 1.6.0

## Suggested inspection (read-only)
- `python -m pip show awsiotsdk`: prints the installed version. Run with the environment that serves production active.
- Maven software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk: check the installed version with your package manager.
- `npm ls aws-iot-device-sdk-v2 --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on awsiotsdk, software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk, aws-iot-device-sdk-v2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-j3f7-7rmc-6wqj (OSV record GHSA-j3f7-7rmc-6wqj lists affected ranges: Maven software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk >=0 =0 =0 <1.7.0 (fixed))
- Verified: https://github.com/advisories/GHSA-j3f7-7rmc-6wqj (GitHub-reviewed advisory GHSA-j3f7-7rmc-6wqj lists affected ranges: Maven software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdk >=0 =0 =0 <1.7.0)

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