CVE-2026-102551 in FreeRTOS-Plus-TCP
Summary
by MITRE • 10/16/2026
Improper verification of the source of a communication channel in the IPv6 Router Advertisement handler in Amazon FreeRTOS-Plus-TCP before V4.4.2 might allow a remote third-party to influence an endpoint's IPv6 default gateway, on-link prefix, and address configuration via a crafted Router Advertisement.
To remediate this issue, users should upgrade to version V4.4.2.
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Analysis
by VulDB Data Team • 10/16/2026
The vulnerability identified in Amazon FreeRTOS-Plus-TCP prior to version 4.4.2 represents a critical failure in the validation of network control messages within IPv6-enabled embedded systems. Specifically, the flaw resides in the Router Advertisement handler, which is responsible for processing ICMPv6 packets that convey essential networking parameters such as default gateways, on-link prefixes, and address configuration details. In a standard IPv6 deployment, devices rely on these advertisements to automatically configure their network interfaces without manual intervention or reliance on external DHCP servers. The core technical deficiency lies in the absence of rigorous source verification for these communication channels. When an endpoint receives a Router Advertisement packet, it fails to adequately authenticate or validate that the message originates from a trusted and authorized router within the local link segment. This lack of cryptographic authentication allows any device capable of injecting packets into the network layer to masquerade as a legitimate gateway.
From an operational perspective, this vulnerability enables a remote third-party actor to perform unauthorized manipulation of the endpoint's networking stack. By crafting malicious Router Advertisement messages, an attacker can redirect traffic intended for external networks through their own controlled infrastructure. This effectively compromises the integrity and confidentiality of all network communications originating from or destined for the affected device. The impact extends beyond simple routing changes; it facilitates man-in-the-middle attacks where sensitive data can be intercepted, modified, or dropped entirely. Furthermore, an attacker could isolate the endpoint by advertising a non-existent default gateway or configuring invalid on-link prefixes, resulting in a denial of service that disrupts connectivity and potentially halts critical operations in IoT deployments that depend on continuous network access for telemetry updates or command execution.
This vulnerability aligns with CWE-295, which describes Improper Certificate Validation, as the system fails to properly verify the authenticity of the source sending sensitive configuration data. It also maps directly to MITRE ATT&CK technique T1046, Network Service Discovery, and more specifically T1037.004, Router Advertisement-based Traffic Redirection. In this context, the attacker leverages legitimate network protocols to establish a foothold or redirect traffic without triggering typical intrusion detection systems that focus on payload content rather than protocol behavior anomalies. The exploitation requires no prior authentication within the application layer, making it particularly dangerous in environments where devices are deployed with minimal security configurations and assume trust based solely on local link presence.
To mitigate this risk, organizations must prioritize upgrading Amazon FreeRTOS-Plus-TCP to version 4.4.2 or later, which implements proper verification mechanisms for Router Advertisement sources. In addition to software updates, defensive measures should include the deployment of IPv6 Neighbor Discovery Protocol (NDP) security extensions such as SEND if supported by the hardware and network infrastructure. Network segmentation strategies can also limit the blast radius by isolating IoT devices from critical management networks. Regular audits of network configurations and monitoring for anomalous Router Advertisement traffic patterns are recommended to detect potential exploitation attempts in real-time, ensuring that embedded systems maintain their intended operational integrity against protocol-level attacks.