CVE-2025-55084 is a buffer over-read vulnerability classified under CWE-126, discovered in the Eclipse Foundation's NetX Duo TCP/IP stack, specifically in versions prior to 6.4.4. The flaw exists in the _nx_secure_tls_proc_clienthello_supported_versions_extension() function, which handles the parsing of the TLS ClientHello message's supported versions extension. An incorrect bounds check allows the function to read beyond the allocated buffer, potentially leaking adjacent memory contents. This vulnerability is exploitable remotely without requiring authentication or user interaction, as it occurs during the TLS handshake process initiated by a client. Although the vulnerability does not directly allow code execution or denial of service, the exposure of memory contents can lead to sensitive information disclosure, undermining confidentiality. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and low impact on confidentiality (VC:L), with no impact on integrity or availability. No public exploits have been reported yet, but the nature of the vulnerability makes it a candidate for future exploitation, especially in embedded systems and IoT devices using NetX Duo for secure communications. The lack of a patch link suggests that a fix may be pending or recently released. Organizations relying on NetX Duo should monitor updates closely and prepare to apply patches promptly.

The primary impact of CVE-2025-55084 is the potential exposure of sensitive memory contents during the TLS handshake, which can lead to confidentiality breaches. For European organizations, especially those deploying embedded systems, industrial control systems, or IoT devices that utilize NetX Duo for secure communications, this vulnerability could expose cryptographic material or other sensitive data processed during TLS negotiation. While the vulnerability does not allow direct code execution or service disruption, the leakage of memory data can facilitate further attacks, such as session hijacking or cryptographic key recovery. Sectors like manufacturing, automotive, healthcare, and critical infrastructure in Europe that increasingly rely on embedded TLS stacks are at heightened risk. The remote exploitability without authentication increases the threat surface, potentially allowing attackers to scan and target vulnerable devices across networks. Given the medium severity and no known exploits currently, the immediate risk is moderate but could escalate if exploit code becomes available.

1. Upgrade to NetX Duo version 6.4.4 or later as soon as the patch is available to ensure the bounds check issue is resolved. 2. In the interim, implement network-level protections such as firewall rules to restrict access to devices running vulnerable NetX Duo versions, especially blocking untrusted sources from initiating TLS handshakes. 3. Conduct an inventory of all embedded and IoT devices using NetX Duo within the organization to identify vulnerable endpoints. 4. Monitor network traffic for anomalous TLS ClientHello messages that could indicate exploitation attempts. 5. Collaborate with device vendors to confirm patch availability and deployment timelines. 6. Review TLS implementation configurations to ensure strict adherence to protocol specifications and consider additional runtime protections like memory safety checks if feasible. 7. Incorporate this vulnerability into vulnerability management and incident response plans to enable rapid detection and remediation. 8. Educate relevant teams about the risks of buffer over-read vulnerabilities in embedded TLS stacks to improve proactive defense measures.