CVE-2026-7426

High

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.

SeverityHigh

CVSS8.1

Exploit probability—

ProductAmazon Freertos-plus-tcp

PublishedApr 29, 2026

First seenApr 29, 2026

Weakness typeCWE-787Out-of-bounds write

How to fix

Update

amazon freertos-plus-tcp4.2.6, 4.4.1 or later

Patches

Vendor advisories

aws.amazon.com/security/security-bulletins/2026-023-aws/

Affected products

Product	Affected versions	Fixed in
amazon freertos-plus-tcp	4.0.0 ≤ v < 4.2.6, 4.3.0 ≤ v < 4.4.1	4.2.6, 4.4.1

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