CVE-2026-7423 MEDIUM

CVE-2026-7423: Integer Underflow in ICMP Echo Reply Processing in FreeRTOS-Plus-TCP

Vendor Aws
Product FreeRTOS-Plus-TCP
Weakness CWE-191
Published April 29, 2026
Last update April 29, 2026

CVSS base score

5.3/10
Attack vector Adjacent
Attack complexity High
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 29, 2026 CVE published
April 29, 2026 Record updated