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


- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 16 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** GHSA-pjq5-fqrr-g6pv

## What is CVE-2026-102551?

CVE-2026-102551 is a critical vulnerability in FreeRTOS-Plus-TCP, published on 16 Oct 2026. 

### 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.

Weakness: CWE-940 (Improper Verification of Source of a Communication Channel)

## Which versions are affected by CVE-2026-102551?


## How do I fix CVE-2026-102551?

No fix has been published for CVE-2026-102551 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-102551 being exploited?

There is no known exploitation of CVE-2026-102551 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-102551 and fix it if it is affected.

What it is: CVE-2026-102551 is a critical vulnerability in FreeRTOS-Plus-TCP, published on 16 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-102551 in the wild and no public exploit code.

Affected product: FreeRTOS-Plus-TCP. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-102551/ (Markdown: https://insights.sbomify.com/CVE-2026-102551/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-102551
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-102551
- OSV: https://osv.dev/vulnerability/CVE-2026-102551

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-102551/
Summaries are generated and may contain mistakes; the official description above is the record.