Signal K Server vulnerable to JWT Token Theft via WebSocket Enumeration and Unauthenticated Polling

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-68620
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-01-01 19:15:53 UTC
Updated2026-10-01 08:10:00 UTC
DescriptionSignal 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 `ACCESS_REQUEST` 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 `allow_readonly` 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.

Risk And Classification

Primary CVSS: v3.1 9.1 CRITICAL from [email protected]

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

EPSS: 0.005390000 probability, percentile 0.434090000 (date 2026-10-04)

Problem Types: CWE-288 | CWE-288 CWE-288: Authentication Bypass Using an Alternate Path or Channel

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
3.1CNADECLARED9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Signalk Signal K Server All All All All
Application Signalk Signal K Server 2.19.0 beta1 All All
Application Signalk Signal K Server 2.19.0 beta2 All All
Application Signalk Signal K Server 2.19.0 beta3 All All
Application Signalk Signal K Server 2.19.0 beta4 All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA SignalK Signalk-server affected < 2.19.0 Not specified

References

ReferenceSourceLinkTags
github.com/SignalK/signalk-server/releases/tag/v2.19.0 [email protected] github.com Release Notes
github.com/SignalK/signalk-server/security/advisories/GHSA-fq56-hvg6-wvm5 [email protected] github.com Exploit, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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