CVE-2026-55591: Signal K Server: Server-Side Request Forgery via Remote Connection Endpoints

June 18, 2026

signalk-server versions up to and including 2.27.0 contain a Server-Side Request Forgery (SSRF) vulnerability in three administrative endpoints used for remote Signal K server connection management. The makeRemoteRequest() function accepts attacker-controlled host, port, useTLS, and selfsignedcert parameters without any validation, allowing an attacker to force the server to make arbitrary HTTP/HTTPS requests to internal network resources, cloud metadata services, and other unintended destinations.

When security is not configured (the default state), these endpoints require no authentication.

References

Code Behaviors & Features

Detect and mitigate CVE-2026-55591 with GitLab Dependency Scanning

Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Dependency Scanning using SBOM also detects vulnerabilities from proprietary advisories that this site does not include. Learn more about Dependency Scanning using SBOM →