Vulnerability · Published Apr 29, 2026 · Assigned by AMZN

CVE-2026-7424Integer Underflow in DHCPv6 Sub-Option Parser in FreeRTOS-Plus-TCP

High 8.1

In plain English

A high-severity security flaw in FreeRTOS-Plus-TCP from AWS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities).

Severity (CVSS 3.1)8.1High

Exploit odds (30 days)0.2%top 87.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Integer underflow in the DHCPv6 sub-option parser in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adjacent network actor to corrupt the device's IPv6 address assignment, DNS configuration, and lease times, and to cause a denial of service (permanent IP task freeze requiring hardware reset) by sending a single crafted DHCPv6 packet. The issue is present whenever DHCPv6 is enabled. To mitigate this issue, users should upgrade to version V4.2.6 or V4.4.1 or newer.

Affected products (as reported)

Vendor	Product	Versions
AWS	FreeRTOS-Plus-TCP	4.0.0 – before 4.2.64.3.0 – before 4.4.1

Weakness: CWE-191 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

References

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 patch
https://aws.amazon.com/security/security-bulletins/2026-022-aws/ vendor-advisory
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-wrhm-c99p-2p8g third-party-advisory