Memory allocation with excessive size value in the MQTT 3.1.1 compatibility adapter in AWS aws-c-mqtt before 0.16.2 might allow a remote actor to cause a denial of service of the client application. To remediate this issue, users should upgrade to aws-c-mqtt 0.16.2 or later, or to an AWS Common Runtime or AWS IoT Device SDK release that bundles it.
https://github.com/awslabs/aws-c-mqtt/security/advisories/GHSA-g3x5-86mr-65p5
https://github.com/awslabs/aws-c-mqtt/releases/tag/v0.16.2
https://aws.amazon.com/security/security-bulletins/2026-147-aws/
Published: 2026-10-22
Updated: 2026-10-22
Base Score: 7.8
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C
Severity: High
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity: High
Base Score: 8.2
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: High