---
title: "CVE-2025-68620: Signal K Server vulnerable to JWT Token Theft via WebSocket Enumeration and Unauthenticated Polling"
url: https://erroneo.us/security/cve/CVE-2025-68620/
description: "CVE-2025-68620 (signalk-server (npm)): Signal K Server is a server application that runs on a central hub in a boat. Versions prior to 2.19.0 expose two…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-01-01
date_modified: 2026-01-02
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-68620"
kev: false
cvss: 9.1
epss: 0.00539
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2025-68620: Signal K Server vulnerable to JWT Token Theft via WebSocket Enumeration and Unauthenticated Polling

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.5% , percentile 45: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 45% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes signalk-server (npm) < 2.19.0, fixed in 2.19.0 . Check your lockfile, including transitive dependencies.

## What it is

Signal K Server is a server application that runs on a central hub in a boat. Versions prior to 2.19.0 expose two features that can be chained together to steal JWT authentication tokens without any prior authentication. The attack combines WebSocket-based request enumeration with unauthenticated polling of access request status. The first is Unauthenticated WebSocket Request Enumeration: When a WebSocket client connects to the SignalK stream endpoint with the serverevents=all query parameter, the server sends all cached server events including ACCESSREQUEST events that contain details about pending access requests. The startServerEvents function iterates over app.lastServerEvents and writes each cached event to any connected client without verifying authorization level. Since WebSocket connections are allowed for readonly users (which includes unauthenticated users when allowreadonly is true), attackers receive these events containing request IDs, client identifiers, descriptions, requested permissions, and IP addresses. The second is Unauthenticated Token Polling: The access request status endpoint at /signalk/v1/access/requests/:id returns the full state of an access request without requiring authentication. When an administrator approves a request, the response includes the issued JWT token in plaintext. The queryRequest function returns the complete request object including the token field, and the REST endpoint uses readonly authentication, allowing unauthenticated access. An attacker has two paths to exploit these vulnerabilities. Either the attacker creates their own access request (using the IP spoofing vulnerability to craft a convincing spoofed request), then polls their own request ID until an administrator approves it, receiving the JWT token; or the attacker passively monitors the WebSocket stream to discover request IDs from legitimate devices, then polls those IDs and steals the JWT tokens when administrators approve them, hijacking legitimate device credentials. Both paths require zero authentication and enable complete authentication bypass. Version 2.19.0 fixes the underlying issues.

## Affected packages

- npm `signalk-server` < 2.19.0 → fixed: 2.19.0

## Affected products (CVE record)

- SignalK signalk-server: < 2.19.0

## Severity

- GitHub_M CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.54% probability of exploitation activity in the next 30 days; percentile 45.

## Sources

- [GitHub Advisory GHSA-fq56-hvg6-wvm5](https://github.com/advisories/GHSA-fq56-hvg6-wvm5)
- [CVE.org record CVE-2025-68620](https://www.cve.org/CVERecord?id=CVE-2025-68620)
- [NVD entry CVE-2025-68620](https://nvd.nist.gov/vuln/detail/CVE-2025-68620)
- [github.com](https://github.com/SignalK/signalk-server/security/advisories/GHSA-fq56-hvg6-wvm5)
- [github.com](https://github.com/SignalK/signalk-server/releases/tag/v2.19.0)
- [github.com](https://github.com/SignalK/signalk-server/commit/221aff6cd89c56308084d1781b3abbf938605bd3)

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Source page: https://erroneo.us/security/cve/CVE-2025-68620/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt