CVE-2025-56764 is a medium-severity vulnerability affecting the Trivision NC-227WF device firmware version 5.80 (build 20141010). The vulnerability arises from the device's login mechanism, which leaks information about the validity of usernames through distinct error messages. Specifically, when an attacker attempts to log in, the system responds with "Unknown user" if the username does not exist, and "Wrong password" if the username is valid but the password is incorrect. This behavior allows an unauthenticated attacker to enumerate valid usernames without requiring any privileges or user interaction. The vulnerability is classified under CWE-287 (Improper Authentication), indicating that the authentication mechanism fails to properly conceal user existence information. The CVSS v3.1 base score is 6.5, reflecting a medium severity level, with an attack vector of network (remote exploitation), low attack complexity, no privileges required, and no user interaction needed. The impact affects confidentiality and integrity to a limited extent, as the attacker gains knowledge of valid usernames, which can be leveraged for further attacks such as brute force password attempts or social engineering. There are no known exploits in the wild at this time, and no official patches have been linked yet. The vulnerability is specific to the Trivision NC-227WF firmware version 5.80, which is a network-connected device likely used in security or surveillance contexts.

For European organizations, the primary impact of this vulnerability is the exposure of valid usernames on affected Trivision NC-227WF devices. This information disclosure can facilitate targeted brute force or credential stuffing attacks, increasing the risk of unauthorized access. Organizations using these devices in critical infrastructure, corporate security, or surveillance systems could face compromised device control or data leakage if attackers leverage enumerated usernames to gain access. While the vulnerability does not directly allow remote code execution or denial of service, the information gained can be a stepping stone for more severe attacks. Confidentiality is impacted as attackers learn valid usernames, and integrity could be compromised if attackers successfully authenticate using guessed or stolen credentials. Availability is not directly affected. The medium severity rating suggests that while the risk is not critical, it should not be ignored, especially in environments where these devices are deployed in sensitive or high-value contexts. European organizations with extensive deployments of Trivision NC-227WF devices should consider this vulnerability a potential risk vector for targeted attacks.

To mitigate this vulnerability, organizations should implement the following specific measures: 1) Configure the device or associated authentication systems to use generic error messages that do not reveal whether a username exists or not, such as a uniform "Invalid username or password" message. 2) Implement account lockout or throttling mechanisms to limit the number of login attempts from a single source, reducing the effectiveness of username enumeration and brute force attacks. 3) Monitor authentication logs for repeated failed login attempts that may indicate enumeration or brute force activity. 4) Where possible, restrict network access to the device's management interface to trusted IP addresses or via VPN to reduce exposure to external attackers. 5) Regularly update device firmware and monitor vendor advisories for patches addressing this vulnerability. 6) Employ multi-factor authentication (MFA) on device access if supported, to add an additional layer of security beyond username and password. 7) Conduct security awareness training for administrators to recognize and respond to suspicious login activity. These steps go beyond generic advice by focusing on configuration changes, access controls, and monitoring tailored to the specific vulnerability and device context.