EUVD-2026-278806

fkie_cve-2026-33951

Signal K Server is a server application that runs on a central hub in a boat. Prior to version 2.24.0-beta.1, the SignalK Server exposes an unauthenticated HTTP endpoint that allows remote attackers to modify navigation data source priorities. This endpoint, accessible via PUT /signalk/v1/api/sourcePriorities, does not enforce authentication or authorization checks and directly assigns user-controlled input to the server configuration. As a result, attackers can influence which GPS, AIS, or other sensor data sources are trusted by the system. The changes are immediately applied and persisted to disk, allowing the manipulation to survive server restarts. This issue has been patched in version 2.24.0-beta.1.

GHSA-gfmv-vh34-h2x5 — Signal K Server: Unauthenticated Source Priorities Manipulation

Affected: npm: signalk-server

## Summary

The SignalK Server exposes an unauthenticated HTTP endpoint that allows remote attackers to modify navigation data source priorities. This endpoint, accessible via `PUT /signalk/v1/api/sourcePriorities`, does not enforce authentication or authorization checks and directly assigns user-controlled input to the server configuration.

As a result, attackers can influence which GPS, AIS, or other sensor data sources are trusted by the system. The changes are immediately applied and persisted to disk, allowing the manipulation to survive server restarts.

### Affected Component - **File**: `src/serverroutes.ts` - **Endpoint**: `PUT /signalk/v1/api/sourcePriorities` (also accessible at `/skServer/sourcePriorities`) - **Lines**: 1064-1076 - **Function**: Source priorities configuration handler

### Vulnerable Code

```typescript // src/serverroutes.ts - Lines 1064-1076 app.put( `${SERVERROUTESPREFIX}/sourcePriorities`, (req: Request, res: Response) => { app.config.settings.sourcePriorities = req.body app.activateSourcePriorities() writeSettingsFile(app, app.config.settings, (err: any) => { if (err) { res .status(500) .send('Unable to save to sourcePrefences in settings file') } else { res.json({ result: 'ok' }) } }) } ) ``` ## Vulnerability Characteristics

**Missing Authentication**: The endpoint has zero authentication middleware, allowing unauthenticated access from any network-adjacent attack…

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EUVD-2026-278806

fkie_cve-2026-33951

GHSA-gfmv-vh34-h2x5 — Signal K Server: Unauthenticated Source Priorities Manipulation