CVE-2026-103416: CWE-787 Out-of-bounds write in Eclipse Foundation Eclipse ThreadX - NetX Duo

This vulnerability (CWE-787) involves an out-of-bounds write in the TLS 1.3 handshake message cache within Eclipse ThreadX NetX Duo versions up to 6.5.1.202602. When a handshake message exceeds the allocated cache size, it overwrites memory beyond the cache into the session control block, which contains pointers. An attacker controlling or impersonating a server can exploit this by sending an oversized handshake message before certificate authentication completes, bypassing the need for a valid server certificate.

Successful exploitation can lead to memory corruption in the client, potentially allowing arbitrary code execution or denial of service. Because the attack can be initiated before server certificate authentication, it lowers the barrier for exploitation by malicious or compromised servers. The CVSS 4.0 base score is 9.3, indicating critical severity with network attack vector, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability.

No official patch or remediation details are provided in the available data. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid connecting to untrusted or potentially malicious TLS 1.3 servers. Monitor vendor channels for updates and apply patches promptly once released.