Vulnerability · Published Oct 16, 2026 · Assigned by AMZN

CVE-2026-102551Improper verification of the source of a communication channel in FreeRTOS-Plus-TCP Router Advertisement handling

High 7.7

In plain English

A high-severity security flaw in FreeRTOS-Plus-TCP from FreeRTOS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities).

Severity (CVSS 3.1)7.7High

Exploit odds (30 days)0.3%top 80.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Improper verification of the source of a communication channel in the IPv6 Router Advertisement handler in Amazon FreeRTOS-Plus-TCP before V4.4.2 might allow a remote third-party to influence an endpoint's IPv6 default gateway, on-link prefix, and address configuration via a crafted Router Advertisement. To remediate this issue, users should upgrade to version V4.4.2.

Affected products (as reported)

Vendor	Product	Versions
FreeRTOS	FreeRTOS-Plus-TCP	0 – through 4.4.1

Weakness: CWE-940 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L

References

https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.2 release-notes, patch
https://aws.amazon.com/security/security-bulletins/2026-139-aws/ vendor-advisory
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-pjq5-fqrr-g6pv third-party-advisory