# CVE-2026-7426: Amazon FreeRTOS-Plus-TCP memory safety issues in IPv6 Router Advertisement

Source: https://junglewise.ai/threats/cve-2026-7425-amazon-freertos-plus-tcp-memory-safety-issues-in-ipv6-router  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-29. Updated: 2026-05-15  
License: CC BY 4.0 with a link back

CVE-2026-7426 · Severity: high · CVSS 6.5 · Published 2026-04-29

FreeRTOS-Plus-TCP is a networking library used by embedded devices to communicate over the internet and local networks. Vulnerabilities in how the library handles network configuration messages could allow a malicious device on the same local network to crash a device or potentially gain unauthorized access. This could lead to service disruptions or the compromise of sensitive data handled by the embedded system.

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

## Quick answers

**Is CVE-2026-7426 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-7426 being exploited in the wild.

**How severe is CVE-2026-7426?** High severity, with a CVSS score of 6.5, published 29 April 2026.

**Which products and versions are affected?** Amazon Web Services FreeRTOS-Plus-TCP >=V4.0.0, <=V4.2.5; >=V4.3.0, <=V4.4.0.

**Is there a fix for CVE-2026-7426?** A patch was published on 2026-04-29: Fixed in versions V4.4.1 and V4.2.6 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-7426 attacked?** It is attacked from the adjacent network, in a software library.

**Am I affected by CVE-2026-7426?** Check whether you run Amazon AWS, Amazon Freertos-Plus-Tcp or Amazon Web Services 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.

## Technical details

The FreeRTOS-Plus-TCP stack is vulnerable to out-of-bounds read (CVE-2026-7425) and out-of-bounds write (CVE-2026-7426) conditions within the IPv6 Router Advertisement (RA) option parser. The root cause is insufficient validation of length fields in incoming RA packets, which allows memory operations to occur outside of intended buffer boundaries. An attacker on the same local network segment can exploit these flaws by sending specially crafted RA packets. No authentication or user interaction is required for exploitation. The issues have been addressed in versions V4.4.1 and V4.2.6.

## Affected products

- Amazon Web Services FreeRTOS-Plus-TCP >=V4.0.0, <=V4.2.5; >=V4.3.0, <=V4.4.0

## Identifiers

- CVE-2026-7426
- CVE-2026-7425

## Timeline

- 2026-04-29: disclosed
- 2026-04-29: patched: Fixed in versions V4.4.1 and V4.2.6

## References

- [https://aws.amazon.com/security/security-bulletins/rss/2026-023-aws/](https://aws.amazon.com/security/security-bulletins/rss/2026-023-aws/)

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