Eclipse NetX Duo up to 6.5.1.202602 TLS Client buffer overflow

Summaryinfo

A vulnerability labeled as very critical has been found in Eclipse NetX Duo up to 6.5.1.202602. Affected is an unknown function of the component TLS Client. The manipulation results in buffer overflow. This vulnerability is identified as CVE-2026-103415. The attack can be executed remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as very critical, was found in Eclipse NetX Duo up to 6.5.1.202602. Affected is an unknown part of the component TLS Client. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-103415 since 09/30/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/14/2026).

Upgrading to version 6.5.2.202603 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• Eclipse

Name

• NetX Duo

Version

• 6.5.1.202602

License

• open-source

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CPE 2.2info

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