CVE-2025-11616 is a buffer over-read vulnerability classified under CWE-126 found in AWS FreeRTOS-Plus-TCP version 4.0.0. The vulnerability stems from inadequate validation of ICMPv6 packets during processing, specifically when packets of certain message types are smaller than the expected size. This causes the software to read beyond the allocated buffer boundaries, potentially exposing sensitive memory contents or causing application crashes. The flaw affects only IPv6-enabled applications using FreeRTOS-Plus-TCP, a TCP/IP stack commonly used in embedded and IoT devices. The vulnerability can be exploited remotely over the network without authentication or user interaction, as ICMPv6 packets can be sent by an attacker to trigger the out-of-bounds read. However, the impact is limited to information disclosure or denial of service rather than code execution. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and low impact on confidentiality, integrity, and availability (VC:L, VI:N, VA:L). No known exploits have been reported in the wild yet. The recommended mitigation is upgrading to the latest FreeRTOS-Plus-TCP version where the vulnerability is patched and ensuring any forks or derivative implementations incorporate these fixes. Given the nature of embedded systems, patching may require coordinated firmware updates. Monitoring for unusual ICMPv6 traffic patterns can help detect exploitation attempts.

For European organizations, the vulnerability poses a moderate risk primarily to embedded and IoT devices running FreeRTOS-Plus-TCP with IPv6 enabled. Potential impacts include unauthorized disclosure of memory contents, which could leak sensitive information, and denial of service through application crashes. Critical infrastructure sectors such as energy, manufacturing, transportation, and healthcare that deploy embedded systems with FreeRTOS stacks may face operational disruptions or data exposure. The network-based attack vector means attackers can exploit the flaw remotely without authentication, increasing the threat surface. However, the absence of privilege escalation or code execution limits the severity. Organizations relying on IPv6 networks and embedded devices should consider this vulnerability in their risk assessments. Failure to patch could lead to targeted attacks exploiting the flaw to gather intelligence or disrupt device functionality, impacting service availability and data confidentiality.

1. Upgrade all FreeRTOS-Plus-TCP deployments to the latest version that includes the patch for CVE-2025-11616. 2. Audit and patch any forked or derivative codebases to ensure they incorporate the fix. 3. Implement network-level filtering to restrict or monitor ICMPv6 traffic, especially from untrusted sources, to reduce exposure to malicious packets. 4. Deploy intrusion detection systems (IDS) or anomaly detection tools capable of identifying unusual ICMPv6 packet patterns indicative of exploitation attempts. 5. Coordinate firmware update processes for embedded devices to ensure timely patch deployment, including devices in remote or hard-to-access locations. 6. Conduct vulnerability scanning and penetration testing focused on IPv6 ICMPv6 handling in embedded systems. 7. Maintain an inventory of devices using FreeRTOS-Plus-TCP with IPv6 enabled to prioritize remediation efforts. 8. Educate operational technology (OT) and IoT security teams about the vulnerability and signs of exploitation.