CVE-2026-7426: Amazon Freertos-Plus-TCP

High severity, CVSS 8.1. EPSS: 0.4% chance of exploitation in the next 30 days.

Insufficient validation of the prefix length field in IPv6 Router Advertisement processing in FreeRTOS-Plus-TCP before V4.2.6 and V4.4.1 allows an adjacent network actor to cause memory corruption by sending a crafted Router Advertisement with a prefix length value exceeding the maximum valid length, resulting in a heap buffer overflow. Users processing IPv4 RA only are not impacted. To mitigate this issue, users should upgrade to the fixed version when available.

Affected products

• Amazon Freertos-Plus-TCP: from 4.0.0, before 4.2.6 (fixed in 4.2.6); from 4.3.0, before 4.4.1 (fixed in 4.4.1)

Published 2026-04-29. Last modified 2026-06-17.