Out-of-bounds write in NetX Duo - CVE-2026-103415
Published: November 9, 2026
Vulnerability identifier: #VU162958
CSH Severity: High
CVSS v4: 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]
CVE-ID: CVE-2026-103415
CWE-ID: CWE-787
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an unauthenticated remote attacker to corrupt memory in NetX Duo TLS clients before certificate authentication.
The vulnerability exists due to unchecked copying of HelloRetryRequest cookies into the second ClientHello packet when TLS 1.3 is explicitly enabled and ECC ciphersuites are enabled. An unauthenticated remote attacker can impersonate the client's endpoint and supply a cookie exceeding the outgoing packet's capacity, overwriting adjacent memory and executing an attacker-selected callback in a demonstrated test layout.
Affected software
NetX Duo
How to mitigate CVE-2026-103415
Install security update from vendor's website.
NetX Duo - update to 6.5.2.202603