CVE-2025-66398: Signalk Signal K Server

High severity, CVSS 8.8. EPSS: 19.9% chance of exploitation in the next 30 days.

Signal K Server is a server application that runs on a central hub in a boat. Prior to version 2.19.0, an unauthenticated attacker can pollute the internal state (`restoreFilePath`) of the server via the `/skServer/validateBackup` endpoint. This allows the attacker to hijack the administrator's "Restore" functionality to overwrite critical server configuration files (e.g., `security.json`, `package.json`), leading to account takeover and Remote Code Execution (RCE). Version 2.19.0 patches this vulnerability.

Affected products

• Signalk Signal K Server: before 2.19.0 (fixed in 2.19.0)

Published 2026-01-01. Last modified 2026-10-07.