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CVE-2021-40831

23
FAUCET Score

CVE-2021-40831 affects AWS IoT Device SDK v2 for Java, Python, C++, and Node.js on macOS, where a user-supplied Certificate Authority (CA) is appended rather than overriding the system’s trust store, and SNI validation is not enforced. This allows TLS handshakes to succeed if verified by either the user-supplied CA or the system's default trust-store. With a CVSS score of 7.2 (HIGH), this vulnerability could allow attackers with access to a host's trust stores or compromised CAs to spoof the MQTT broker, potentially dropping or altering traffic, though they cannot forward data without the user's private keys. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
0.10.7CPE matchmatch criteria
cpe:2.3:a:amazon:amazon_web_services_aws-c-io:0.10.7:*:*:*:*:*:*:*
< 1.5.0CPE matchmatch criteria
cpe:2.3:a:amazon:amazon_web_services_internet_of_things_device_software_development_kit_v2:*:*:*:*:*:java:*:*
< 1.6.0CPE matchmatch criteria
cpe:2.3:a:amazon:amazon_web_services_internet_of_things_device_software_development_kit_v2:*:*:*:*:*:node.js:*:*
< 1.7.0CPE matchmatch criteria
cpe:2.3:a:amazon:amazon_web_services_internet_of_things_device_software_development_kit_v2:*:*:*:*:*:python:*:*
< 1.14.0CPE matchmatch criteria
cpe:2.3:a:amazon:amazon_web_services_internet_of_things_device_software_development_kit_v2:*:*:*:*:*:c\+\+:*:*

CVSS Data

CVSS version used by this source: 3.1

6.3MEDIUM

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

Attack Vector
ADJACENT_NETWORK
Attack Complexity
HIGH
Privileges Required
HIGH
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
0.4
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.61%
Probability of exploitation in next 30 days
EPSS Percentile
45.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0061 is in the 24th percentile among its peer group of 5,537 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.3 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

mavenpatch availablevia ghsa
Product: software.amazon.awssdk.iotdevicesdk:aws-iot-device-sdkFixed in: 1.5.0
npmpatch availablevia ghsa
Product: aws-iot-device-sdk-v2Fixed in: 1.6.0
pippatch availablevia ghsa
Product: awsiotsdkFixed in: 1.7.0

Vendor Advisories (1)

mavenGHSA-j3f7-7rmc-6wqjhigh

Improper certificate management in AWS IoT Device SDK v2

Nov 24, 2021

References

github.com / aws/aws-iot-device-sdk-cpp-v2
Product
github.com / aws/aws-iot-device-sdk-java-v2
Product
github.com / aws/aws-iot-device-sdk-js-v2
Product
github.com / aws/aws-iot-device-sdk-python-v2
Product
github.com / awslabs/aws-c-io
Product