CVE-2025-41702 is a critical vulnerability identified in the Welotec EG400Mk2-D11001-000101 device, specifically affecting versions from 0.0.0 up to v1.8.0. The core issue stems from the use of a hard-coded cryptographic key embedded within the egOS WebGUI backend. This key is used as the secret for signing JSON Web Tokens (JWT) with the HS256 algorithm. Because the secret key is hard-coded and accessible to the default user, an unauthenticated remote attacker can extract this key and generate valid JWT tokens. This capability allows the attacker to bypass authentication and authorization mechanisms entirely, gaining unauthorized access to the device's management interface or backend services. The vulnerability is classified under CWE-321 (Use of Hard-coded Cryptographic Key), which is a well-known weakness that compromises the confidentiality and integrity of cryptographic operations. The CVSS v3.1 score of 9.8 (critical) reflects the high severity due to the vulnerability's network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and full impact on confidentiality, integrity, and availability (C:H/I:H/A:H). Although no known exploits have been reported in the wild yet, the straightforward exploitation path and the critical impact make this vulnerability a significant threat. The lack of available patches at the time of publication further exacerbates the risk, necessitating immediate mitigation efforts by affected organizations.

For European organizations using the Welotec EG400Mk2-D11001-000101 device, this vulnerability poses a severe risk. The ability for unauthenticated attackers to generate valid authentication tokens means that attackers can gain full administrative access remotely without any credentials. This can lead to unauthorized configuration changes, data exfiltration, service disruption, or pivoting within the network. Critical infrastructure or industrial control systems relying on these devices could face operational downtime or safety risks. Confidential data managed or transmitted by the device could be exposed or manipulated, violating data protection regulations such as GDPR. The high severity and ease of exploitation mean that attackers could rapidly compromise multiple devices across an organization, potentially leading to widespread service outages or breaches. Additionally, the lack of patches increases the window of exposure, making proactive mitigation essential. The impact extends beyond individual organizations to sectors such as manufacturing, utilities, and telecommunications where Welotec devices might be deployed.

Given the absence of official patches, European organizations should immediately implement compensating controls. First, restrict network access to the affected devices by placing them behind firewalls or VPNs, limiting exposure to trusted internal networks only. Employ network segmentation to isolate these devices from critical systems and sensitive data. Monitor network traffic for anomalous JWT token generation or unusual authentication attempts. If possible, disable or restrict the egOS WebGUI backend access until a patch is available. Organizations should also consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block unauthorized JWT tokens or suspicious API calls. Regularly audit device configurations and logs for signs of compromise. Engage with Welotec support channels to obtain updates or workarounds. Finally, plan for timely patch deployment once available and consider alternative devices if the risk cannot be adequately mitigated.