CVE-2025-66398 CRITICAL

CVE-2025-66398: Signal K Server has Unauthenticated State Pollution leading to Remote Code Execution (RCE)

Vendor Signalk
Product signalk-server
Weakness CWE-78
Published January 1, 2026
Last update January 5, 2026
View on NVD All CVEs

CVSS base score

9.7/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

January 1, 2026 CVE published
January 5, 2026 Record updated