CVE-2026-7426

HIGH

Out-of-Bounds Write via Unsanitized Prefix Length in Router Advertisement Processing in FreeRTOS-Plus-TCP

Title source: cna

Description

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.

References (4)

[Patch] https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1

[Patch] https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6

[Vendor Advisory] https://aws.amazon.com/security/security-bulletins/2026-023-aws/

[Third Party Advisory] https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-97qg-4359-xm3x

Scores

CVSS v3 8.1

EPSS 0.0001

EPSS Percentile 3.4%

Attack Vector ADJACENT_NETWORK

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

CISA SSVC

Vulnrichment

Exploitation none

Automatable no

Technical Impact partial

Details

CWE

CWE-787

Status published

Products (4)

AWS/FreeRTOS-Plus-TCP 4.0.0 - 4.2.6

AWS/FreeRTOS-Plus-TCP 4.2.6

AWS/FreeRTOS-Plus-TCP 4.3.0 - 4.4.1

AWS/FreeRTOS-Plus-TCP 4.4.1

Published Apr 29, 2026

Tracked Since Apr 30, 2026