CVE-2025-11617 is a vulnerability identified in AWS FreeRTOS-Plus-TCP version 4.0.0, specifically within the IPv6 packet processing component. The root cause is a missing validation check on the payload length field of incoming IPv6 packets. When an IPv6 packet with an incorrect or malformed payload length is received, the code attempts to read beyond the allocated buffer boundaries, resulting in a buffer over-read condition (CWE-126). This can lead to unintended disclosure of memory contents or cause application crashes due to invalid memory access. The vulnerability only affects applications that utilize IPv6 networking stacks within FreeRTOS-Plus-TCP, leaving IPv4-only deployments unaffected. Exploitation requires sending specially crafted IPv6 packets over the network, with no need for user interaction or elevated privileges, making it remotely exploitable. 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, resulting in a medium severity score of 5.3. No known exploits have been reported in the wild as of the publication date, but the vulnerability poses a risk to embedded and IoT devices relying on FreeRTOS-Plus-TCP for IPv6 connectivity. AWS recommends upgrading to the latest version and ensuring any forks or derivative codebases incorporate the patch to remediate the issue.

For European organizations, the impact of CVE-2025-11617 primarily concerns IoT and embedded device deployments that use FreeRTOS-Plus-TCP with IPv6 enabled. Potential impacts include unauthorized disclosure of sensitive memory data due to buffer over-read, which could leak cryptographic keys, credentials, or other sensitive information stored in memory. Additionally, the vulnerability could cause device instability or crashes, leading to denial of service conditions in critical infrastructure or industrial control systems. Given the increasing adoption of IPv6 in Europe and the proliferation of IoT devices in sectors such as manufacturing, energy, and smart cities, this vulnerability could affect operational technology environments and edge devices. Although the vulnerability does not allow code execution or privilege escalation, the information disclosure and availability impacts could facilitate further attacks or disrupt services. Organizations with large-scale IoT deployments or those integrating FreeRTOS-Plus-TCP in safety-critical systems should consider this vulnerability a significant risk to device reliability and data confidentiality.

1. Upgrade all FreeRTOS-Plus-TCP instances to the latest version provided by AWS that includes the patch for CVE-2025-11617. 2. For organizations maintaining forks or derivative versions of FreeRTOS-Plus-TCP, audit the IPv6 packet processing code to ensure the missing validation check is implemented. 3. Implement network-level filtering to restrict or monitor incoming IPv6 traffic to embedded devices, especially from untrusted sources, to reduce exposure to crafted malicious packets. 4. Employ intrusion detection or anomaly detection systems capable of identifying malformed IPv6 packets targeting FreeRTOS-Plus-TCP devices. 5. Conduct regular security assessments and firmware audits on IoT devices to verify the presence of security patches and validate IPv6 stack integrity. 6. Where feasible, disable IPv6 on devices that do not require it to eliminate the attack surface related to this vulnerability. 7. Collaborate with device manufacturers and vendors to ensure timely updates and security advisories are communicated and applied.