AWS Library Vulnerability Risks Denial of Service

The flaw in the aws-c-mqtt library allows remote actors to force excessive memory usage, impacting versions up to 0.16.2.

Updated on Oct. 23, 2026 in Cybersecurity

AWS Library Vulnerability Risks Denial of Service

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Amazon Web Services has disclosed a memory allocation vulnerability, identified as CVE-2026-115417, within the aws-c-mqtt library. This security flaw allows a remote actor to trigger a denial of service by causing the system to allocate memory with an excessive size.

Why it matters

The vulnerability affects the MQTT 3.1.1 compatibility adapter, posing a potential stability risk to applications integrated with the AWS Common Runtime or AWS IoT Device SDK for C++ v2. Organizations relying on these libraries must address the flaw to maintain service availability.

The vulnerability is categorized as CWE-789, which relates to memory allocation with an excessive size value. Impacted library versions span from 0.9.1 to 0.16.2, affecting the AWS Common Runtime and the AWS IoT Device SDK for C++ v2.

The players

Amazon Web Services

A cloud computing provider offering infrastructure-as-a-service, platform-as-a-service, and serverless computing solutions.

The details

The vulnerability occurs within the MQTT 3.1.1 compatibility adapter, a software component that enables communication using the Message Queuing Telemetry Transport protocol. A remote attacker can exploit this by sending a crafted packet that forces the process to request an excessively large memory allocation. This operation consumes system resources, leading to a denial of service where the application becomes unresponsive or crashes due to memory exhaustion.

October 23, 2026: AWS published the security bulletin for CVE-2026-115417.

The Tech Race

This disclosure highlights the ongoing challenge of securing widely used low-level libraries within IoT ecosystems. It follows the industry-wide focus on neutralizing memory-based exploits defined by the Common Weakness Enumeration list.

Developers and systems engineers currently using versions 0.9.1 through 0.16.2 of the aws-c-mqtt library should audit their applications for exposure. Teams should monitor official AWS channels for the release of an updated library version to mitigate the risk of denial of service.

The takeaway

The vulnerability underscores the importance of monitoring dependencies in IoT and embedded C++ environments for memory-related defects. Users should prioritize updating their library versions as soon as a patch is confirmed and made available by AWS.