# CVE-2026-102551: FreeRTOS-Plus-TCP improper source verification in IPv6 Router Advertisement and DNS resolver

Source: https://junglewise.ai/threats/cve-2026-102551-amp-issue-with-freertos-plus-tcp  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-16. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-102551 · Severity: high · CVSS 7.7 · Published 2026-10-16

FreeRTOS-Plus-TCP is a networking library used in embedded and IoT devices to handle TCP/IP communications. Two validation flaws allow remote attackers to intercept IPv6 traffic or redirect DNS lookups by spoofing network replies, potentially hijacking device connections without authentication.

Technologies: [Amazon AWS](https://junglewise.ai/threats/technologies/aws), [Amazon Freertos-Plus-Tcp](https://junglewise.ai/threats/technologies/amazon-freertos-plus-tcp). Vendors: [Amazon](https://junglewise.ai/threats/vendors/amazon).

## Quick answers

**Is CVE-2026-102551 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-102551 being exploited in the wild.

**How severe is CVE-2026-102551?** High severity, with a CVSS score of 7.7, published 16 October 2026.

**Which products and versions are affected?** Amazon Freertos-Plus-Tcp through 4.4.1.

**Is there a fix for CVE-2026-102551?** Yes: fixed in FreeRTOS-Plus-TCP 4.4.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-102551 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-102551?** Check whether you run Amazon AWS or Amazon Freertos-Plus-Tcp at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in FreeRTOS-Plus-TCP 4.4.2 or later

## Technical details

CVE-2026-102551 is an improper source verification flaw in the IPv6 Router Advertisement handler that fails to validate on-link origin before accepting router configuration, allowing an attacker to influence gateway, prefix, and address settings. CVE-2026-102552 is a similar flaw in the DNS resolver that fails to validate reply origin, allowing DNS cache poisoning. Both are reachable over the network in default configurations.

## Affected products

- Amazon FreeRTOS-Plus-TCP through 4.4.1

## Identifiers

- CVE-2026-102551
- CVE-2026-102552

## Timeline

- 2026-10-16: disclosed

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