Signal K Server is a server application that runs on a central hub in a boat. Prior to 2.28.0, makeRemoteRequest() in src/serverroutes.ts accepted attacker-controlled host, port, useTLS, and selfsignedcert parameters from the testSignalKConnection, requestAccess, and checkAccessRequest endpoints without validating the destination. When security was not configured, addAdminMiddleware() was a no-op in dummysecurity.ts, leaving all three endpoints accessible without authentication. The server could be forced to contact loopback, private, link-local, cloud metadata, or arbitrary external destinations, and selfsignedcert could disable certificate verification for outbound HTTPS requests. The checkAccessRequest endpoint also interpolated requestId into its destination path, allowing traversal to other paths on the selected host. Distinct success, connection-refused, and timeout responses enabled internal port scanning; returned response bodies enabled cloud metadata and internal-service data exfiltration; requestAccess enabled server-side POST requests with attacker-controlled JSON; and access to cluster-internal services could support lateral movement. This issue is fixed in version 2.28.0.
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-q59x-jc9f-gfqf Signal K Server: Server-Side Request Forgery via Remote Connection Endpoints
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Tue, 15 Sep 2026 16:45:00 +0000

Type Values Removed Values Added
First Time appeared Signalk
Signalk signalk-server
Vendors & Products Signalk
Signalk signalk-server

Tue, 15 Sep 2026 15:45:00 +0000

Type Values Removed Values Added
Description Signal K Server is a server application that runs on a central hub in a boat. Prior to 2.28.0, makeRemoteRequest() in src/serverroutes.ts accepted attacker-controlled host, port, useTLS, and selfsignedcert parameters from the testSignalKConnection, requestAccess, and checkAccessRequest endpoints without validating the destination. When security was not configured, addAdminMiddleware() was a no-op in dummysecurity.ts, leaving all three endpoints accessible without authentication. The server could be forced to contact loopback, private, link-local, cloud metadata, or arbitrary external destinations, and selfsignedcert could disable certificate verification for outbound HTTPS requests. The checkAccessRequest endpoint also interpolated requestId into its destination path, allowing traversal to other paths on the selected host. Distinct success, connection-refused, and timeout responses enabled internal port scanning; returned response bodies enabled cloud metadata and internal-service data exfiltration; requestAccess enabled server-side POST requests with attacker-controlled JSON; and access to cluster-internal services could support lateral movement. This issue is fixed in version 2.28.0.
Title Signal K Server: Server-Side Request Forgery via Remote Connection Endpoints
Weaknesses CWE-918
References
Metrics cvssV3_1

{'score': 5.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-15T17:23:51.052Z

Reserved: 2026-06-16T23:18:03.170Z

Link: CVE-2026-55591

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-15T16:17:14.703

Modified: 2026-09-15T16:17:14.703

Link: CVE-2026-55591

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-15T16:30:11Z

Weaknesses