The vulnerability CVE-2025-69203 affects the SignalK signalk-server, a server application used on central hubs in boats to manage device access. Prior to version 2.19.0, the access request system has two interrelated weaknesses. First, when a device requests access, it submits three fields: clientId, description, and permissions. The admin UI prominently displays the description but less clearly shows the permissions, allowing attackers to request admin permissions while describing their request as read-only, misleading administrators. Second, the server trusts the X-Forwarded-For HTTP header without validation to determine the client's IP address. This header is meant to preserve the original client IP behind reverse proxies but can be spoofed by attackers to appear as if requests originate from trusted internal network addresses. Combined with an information disclosure vulnerability that allows enumeration of legitimate device/source names, attackers can impersonate known devices, craft convincing descriptions, and spoof trusted IPs to increase the likelihood of administrator approval for elevated permissions. This results in an authentication bypass by spoofing, enabling unauthorized access and potential control over the server. The vulnerability requires user interaction (administrator approval) but no prior privileges or authentication, making it relatively easy to exploit. The CVSS 3.1 score of 6.3 reflects a medium severity with impacts on confidentiality, integrity, and availability. The recommended mitigation is upgrading to version 2.19.0, which addresses these issues by validating the X-Forwarded-For header and improving the access request UI to prevent misleading descriptions.

For European organizations, especially those in maritime industries or sectors relying on SignalK servers for boat or vessel management, this vulnerability poses a significant risk. Unauthorized attackers can gain admin-level access to critical server infrastructure by exploiting social engineering combined with technical spoofing, potentially leading to unauthorized control over navigation data, device management, or other sensitive operations. This could compromise the confidentiality of vessel data, integrity of device commands, and availability of the server, disrupting maritime operations. Given Europe's extensive coastline and reliance on maritime transport and leisure boating, exploitation could impact commercial shipping companies, port authorities, and private boat owners. Furthermore, compromised systems could be leveraged as footholds for broader network intrusion or espionage, especially in strategic ports or naval facilities. The medium severity indicates a moderate but tangible risk that requires prompt attention to avoid operational disruptions or data breaches.

1. Upgrade all SignalK signalk-server instances to version 2.19.0 or later immediately to apply the fix for this vulnerability. 2. Implement network-level controls to restrict access to the signalk-server management interfaces, limiting exposure to trusted IP ranges and avoiding direct internet exposure. 3. Disable or carefully validate the use of the X-Forwarded-For header in any reverse proxy or load balancer configurations to prevent IP spoofing. 4. Enhance administrator training to recognize social engineering tactics, emphasizing scrutiny of access requests beyond just the description field. 5. Monitor access request logs for unusual patterns, such as repeated requests from unexpected IP addresses or devices. 6. If possible, implement multi-factor authentication or additional verification steps for granting elevated permissions. 7. Conduct regular audits of granted permissions to detect and revoke unauthorized access promptly. 8. Consider network segmentation to isolate the signalk-server from other critical systems to limit lateral movement if compromised.