CVE-2026-7423: Amazon Freertos-Plus-TCP

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Integer underflow in the ICMP and ICMPv6 echo reply handlers in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adjacent network user to cause a denial of service (device crash) when outgoing ping support is enabled, because header sizes are subtracted from a packet length field without validating the field is large enough, resulting in a heap out-of-bounds read of up to approximately 65KB. 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.