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CVE-2021-40828

26
FAUCET Score

CVE-2021-40828 is a high-severity vulnerability affecting AWS IoT Device SDK v2 for Java, Python, C++, and Node.js on Windows, where connections failed to verify server certificate hostnames during TLS handshakes when custom Certificate Authorities were used. This flaw, rated 8.8 HIGH (CVSSv3.1), allows for potential Man-in-the-Middle attacks, leading to compromise of confidentiality, integrity, and availability. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability. Organizations using affected SDK versions on Windows should update to patched versions of the aws-c-io submodule (0.9.13+) to mitigate this risk.

Impacted Technologies

VendorProductVersion(s)CPE
< 0.9.13CPE matchmatch criteria
cpe:2.3:a:amazon:amazon_web_services_aws-c-io:*:*:*:*:*:*:*:*
< 1.3.3CPE matchmatch criteria
cpe:2.3:a:amazon:amazon_web_services_internet_of_things_device_software_development_kit_v2:*:*:*:*:*:java:*:*
< 1.5.1CPE matchmatch criteria
cpe:2.3:a:amazon:amazon_web_services_internet_of_things_device_software_development_kit_v2:*:*:*:*:*:node.js:*:*
< 1.5.18CPE matchmatch criteria
cpe:2.3:a:amazon:amazon_web_services_internet_of_things_device_software_development_kit_v2:*:*:*:*:*:python:*:*
< 1.12.7CPE 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
0.40%
Probability of exploitation in next 30 days
EPSS Percentile
32.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0040 is in the 30th percentile among its peer group of 1,875 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.2 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: 1.3.3
npmpatch availablevia ghsa
Product: aws-iot-device-sdk-v2Fixed in: 1.5.1
pippatch availablevia ghsa
Product: awsiotsdkFixed in: 1.5.18

Vendor Advisories (1)

mavenGHSA-94jq-q5v2-76wjmedium

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