A flaw in the DTLS ClientHello parsing logic of NetX Duo causes an out‑of‑bounds read of up to 255 bytes when the session_id length is copied and the cipher suite list length is validated against the record length instead of the remaining bytes. The affected data are echoed back in the ServerHello, exposing adjacent process memory to an unauthenticated network peer. The vulnerability leads to a confidentiality breach without requiring authentication, though a crash variant can trigger on the very first packet.

The affected product is NetX Duo from the Eclipse Foundation. No specific firmware or release versions are listed in the advisory, so any build containing the vulnerable DTLS ClientHello parser is potentially impacted.

With a CVSS score of 8.8 the flaw is considered high severity. The EPSS score is not provided, and the vulnerability is not listed in CISA’s KEV catalog. The likely attack vector is a remote network connection; an unauthenticated peer can send a crafted DTLS ClientHello to trigger the out‑of‑bounds read and obtain memory contents.