# CVE-2026-103415: Memory corruption in NetX Duo

> A malicious server can trigger a buffer overflow in Eclipse NetX Duo TLS clients during HelloRetryRequest processing, potentially leading to code execution or crashes.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Oct 2026
- **Updated:** 16 Oct 2026
- **Also known as:** GHSA-5pv3-rhf5-gwgq

## What is CVE-2026-103415?

CVE-2026-103415 is a critical memory corruption vulnerability in Eclipse Foundation NetX Duo, published on 14 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

When a TLS 1.3 client processes a HelloRetryRequest, it copies the server's cookie into its second ClientHello without checking that the cookie fits in the outgoing packet. Both the length and the contents of that cookie come from the peer, and the write happens before certificate authentication completes, so a malicious or compromised server can overwrite memory past the caller supplied TLS packet buffer without presenting a certificate.

Only the client path is affected.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-103415?


## How do I fix CVE-2026-103415?

No fix has been published for CVE-2026-103415 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-103415 being exploited?

There is no known exploitation of CVE-2026-103415 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103415 and fix it if it is affected.

What it is: CVE-2026-103415 is a critical memory corruption vulnerability in Eclipse Foundation NetX Duo, published on 14 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-103415 in the wild and no public exploit code.

Affected product: Eclipse Foundation NetX Duo. 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-2026-103415/ (Markdown: https://insights.sbomify.com/CVE-2026-103415/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103415
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103415
- OSV: https://osv.dev/vulnerability/CVE-2026-103415

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103415/
Summaries are generated and may contain mistakes; the official description above is the record.