Live › vulnerability › GHSA-g3x5-86mr-65p5
Go to dashboardThe MQTT 3.1.1 compatibility adapter in aws-c-mqtt, the C library in the AWS Common Runtime and AWS IoT Device SDK for C++ v2, allocates memory using an excessive size value (CWE-789). A remote actor can exploit this to cause a denial of service of the client process.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-24 20:05 UTC. All times on this page are UTC.
Teams whose clients link aws-c-mqtt in the affected range, typically devices or services built on the AWS Common Runtime or AWS IoT Device SDK for C++ v2. Exposure depends on use of the MQTT 3.1.1 compatibility adapter; the advisory's workarounds point to avoiding it in favor of MQTT5. Systems using only a patched version or no aws-c-mqtt at all can skip this.
No product ranges from the sources yet.
>= 0.9.1 and < 0.16.2.v0.16.2 or later.Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
CVE-2026-115417 - Memory allocation with excessive size value in the MQTT 3.1.1 compatibility adapter in aws-c-mqtt
Bulletin ID: 2026-147-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 10/22/2026 13:30 PM PDT
Description:
aws-c-mqtt is a C99 implementation of the MQTT 3.1.1 and MQTT5 specifications, distributed as part of the AWS Common Runtime (CRT) and bundled in the AWS IoT Device SDK for C++ v2. We identified CVE-2026-115417, a memory allocation with excessive size value (CWE-789) in the library's MQTT 3.1.1 compatibility adapter. Under certain conditions, a remote actor could cause a denial of service of the client process.
Impacted versions: >= 0.9.1 AND < 0.16.2
Resolution:
This issue has been addressed in aws-c-mqtt version v0.16.2. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.
Workarounds:
Connect only to trusted MQTT brokers (for example AWS IoT Core, which enforces the negotiated maximum packet size) and use TLS to prevent on-path tampering of broker responses. Where feasible, avoid the MQTT 3.1.1 compatibility adapter in favor of a native MQTT5 or MQTT 3.1.1 client. Upgrading to a fixed version is the complete remediation.
References:
Acknowledgement:
We would like to thank Eunho Kim for collaborating on this issue through the coordinated vulnerability disclosure process.
Please email [email protected] with any security questions or concerns.
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