---
id: CVE-2025-66398
title: Signal K Server is a server application that runs on a central hub in a boat
summary: >-
  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`
  endpoi…
severity: critical
cvss: 9.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H'
cwe:
  - CWE-78
  - CWE-913
vendor: signalk
product: signal_k_server
affected:
  - signal_k_server < 2.19.0
patched:
  - signal_k_server 2.19.0
published: '2026-01-01'
updated: '2026-10-01'
sourceUpdated: '2026-10-01T08:10:00.183'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-66398'
references:
  - url: 'https://github.com/SignalK/signalk-server/releases/tag/v2.19.0'
    label: security-advisories@github.com
  - url: >-
      https://github.com/SignalK/signalk-server/security/advisories/GHSA-w3x5-7c4c-66p9
    label: security-advisories@github.com
tags:
  - nvd
  - exploit-available
epss: 0.1985
epssPercentile: 0.97338
exploits:
  github: 2
  githubRepos:
    - 'https://github.com/joshuavanderpoll/cve-2025-66398'
    - 'https://github.com/showy-headteacher114/cve-2025-66398'
  checkedAt: '2026-10-01T08:40:45.230Z'
exploitAvailable: true
ingestedAt: '2026-10-01T08:40:11.723Z'
---

## Overview

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

- `signal_k_server < 2.19.0`

## Remediation

Upgrade past the affected range:

- `signal_k_server 2.19.0`