CVE-2025-11618 is a vulnerability identified in AWS FreeRTOS-Plus-TCP version 4.0.0, specifically within the UDP/IPv6 packet processing code. The root cause is a missing validation check on the IP version field of incoming UDP/IPv6 packets. When a packet with an incorrect IP version is received, the code dereferences a NULL pointer, leading to an invalid pointer dereference (CWE-476). This results in a denial-of-service condition as the affected application or device may crash or become unresponsive. The vulnerability exclusively affects applications using IPv6, which is increasingly common in modern IoT and embedded systems. Exploitation requires no user interaction and can be performed remotely over the network, with low attack complexity and no privileges required. The CVSS v4.0 score is 5.3 (medium), reflecting the moderate impact on availability and low impact on confidentiality and integrity. No public exploits or active exploitation have been reported to date. The recommended remediation is to upgrade to the latest version of FreeRTOS-Plus-TCP that includes the validation fix. Additionally, organizations maintaining forks or derivative versions of the code must ensure they apply the patch. This vulnerability highlights the importance of robust input validation in network protocol implementations within embedded environments.

For European organizations, the primary impact of CVE-2025-11618 is potential denial of service on embedded and IoT devices running AWS FreeRTOS-Plus-TCP with IPv6 enabled. This can lead to temporary unavailability of critical systems, especially in industrial control, manufacturing automation, smart city infrastructure, and healthcare devices that rely on embedded networking stacks. While the vulnerability does not directly compromise confidentiality or integrity, disruption of availability can have cascading effects on operational continuity and safety. Organizations with large deployments of IoT devices using FreeRTOS-Plus-TCP may face increased risk of network instability or device failures if targeted. The lack of known exploits reduces immediate risk, but the ease of remote exploitation and absence of required user interaction mean attackers could weaponize this vulnerability in the future. European entities involved in critical infrastructure or with stringent uptime requirements should prioritize remediation to avoid service interruptions and potential regulatory scrutiny related to operational resilience.

1. Upgrade all AWS FreeRTOS-Plus-TCP deployments to the latest version that includes the patch for CVE-2025-11618. 2. Audit and patch any forks or derivative codebases that incorporate FreeRTOS-Plus-TCP to ensure the validation fix is applied. 3. Implement network-level filtering to block malformed or suspicious IPv6 UDP packets, especially those with invalid IP version fields, to reduce exposure. 4. Monitor device logs and network traffic for anomalies indicative of malformed packet attempts or crashes. 5. Employ robust device management and update mechanisms to rapidly deploy patches across distributed IoT and embedded device fleets. 6. Where feasible, segment IoT networks to limit exposure of vulnerable devices to untrusted networks. 7. Conduct regular security assessments of embedded network stacks and protocol implementations to identify similar validation weaknesses early. These steps go beyond generic advice by focusing on patch management, network filtering, and proactive monitoring tailored to embedded IPv6 environments.