CVE-2026-103415: Out-Of-Bounds Write Flaw in Eclipse Foundation NetX Duo Scores 9.3 on CVSS

A critical out-of-bounds write tracked as CVE-2026-103415 has been published in the National Vulnerability Database for Eclipse Foundation NetX Duo, with a CVSS base score of 9.3.

At a glance

CVE

CVE-2026-103415

Product

Eclipse Foundation NetX Duo

CVSS

9.3 Critical

Weakness

out-of-bounds write

Exploited

No known exploitation

What is the vulnerability?

The NVD entry states: 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.

Affected versions

Is it being exploited?

There is no public confirmation of exploitation at the time of publication. It does not appear in CISA's Known Exploited Vulnerabilities catalog. We will update this report if that changes.

What should you do?

• Identify whether the affected product and versions run in your environment.
• Apply the vendor update listed in the advisory as soon as it is available.
• Limit network exposure of the affected service until it is patched.
• Monitor the vendor advisory for updated guidance or exploitation reports.

What to do and how to stay safe: CVE-2026-103415

• Vulnerability severity scores ignore your specific architecture and context.
• Exploitability depends on network exposure and user behavior, not just code flaws.
• Prioritization requires continuous asset inventory and threat intelligence alignment.

Risk-based vulnerability management focuses your limited resources on the flaws that actually threaten your business. Start by mapping your critical assets and checking for active exploits to prioritize your backlog.

Step-by-step guide: Risk-Based Vulnerability Management: Prioritize Fixes by Actual Danger

General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.

Frequently asked questions

What is CVE-2026-103415?

CVE-2026-103415 is a out-of-bounds write vulnerability in Eclipse Foundation NetX Duo.

How severe is CVE-2026-103415?

It has a CVSS score of 9.3 Critical.

Is CVE-2026-103415 being exploited?

There is no public confirmation of exploitation at the time of publication.