CVE-2026-7423

Medium

Description

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.

SeverityMedium

CVSS5.3

Exploit probability—

ProductAmazon Freertos-plus-tcp

PublishedApr 29, 2026

First seenApr 29, 2026

Weakness typeCWE-191CWE-191

How to fix

Update

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

Patches

Vendor advisories

aws.amazon.com/security/security-bulletins/2026-021-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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