CVE-2026-33950: Signal K Server Privilege Escalation

CVE-2026-33950 Overview

Signal K Server is a server application that runs on a central hub in a boat for managing marine navigation data and vessel systems. Prior to version 2.24.0-beta.4, a critical privilege escalation vulnerability exists through Admin Role Injection via the /enableSecurity endpoint. An unauthenticated attacker can exploit this flaw to gain full Administrator access to the SignalK server at any time, allowing them to modify sensitive vessel routing data, alter server configurations, and access restricted endpoints.

Critical Impact

Unauthenticated attackers can gain full administrative control over marine navigation systems, potentially compromising vessel safety and routing data integrity.

Affected Products

• Signal K Server versions prior to 2.24.0-beta.4
• Marine vessel systems running vulnerable SignalK server installations
• IoT-connected boat navigation hubs with SignalK integration

Discovery Timeline

• 2026-04-02 - CVE CVE-2026-33950 published to NVD
• 2026-04-02 - Last updated in NVD database

Technical Details for CVE-2026-33950

Vulnerability Analysis

This vulnerability falls under CWE-285 (Improper Authorization), representing a critical authorization bypass that allows privilege escalation without authentication. The flaw resides in the /enableSecurity endpoint, which fails to properly validate whether the requesting user has appropriate permissions before granting administrative privileges.

The attack surface is particularly concerning because Signal K Server instances are designed to run on marine vessels, where they manage critical navigation data, autopilot configurations, and vessel telemetry. Successful exploitation grants attackers the ability to manipulate routing information, potentially leading to dangerous navigation scenarios in maritime environments.

The network-accessible nature of this vulnerability means that any SignalK server exposed to a network—whether local or internet-facing—could be compromised by an unauthenticated remote attacker with no user interaction required.

Root Cause

The root cause is an improper authorization check in the /enableSecurity endpoint. The application fails to verify that the requesting entity has the necessary privileges before processing the security configuration request. This allows any unauthenticated user to inject themselves into the Administrator role, effectively bypassing the entire authentication and authorization model of the application.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker identifies a vulnerable Signal K Server instance and sends a crafted request to the /enableSecurity endpoint. Due to the missing authorization checks, the server processes this request and grants the attacker full administrative privileges.

With administrative access, the attacker can:

• Modify vessel routing and navigation data
• Access and alter server configurations
• Reach restricted API endpoints
• Potentially disrupt vessel operations or navigation systems

The vulnerability mechanism involves improper authorization handling in the security enablement workflow. When the /enableSecurity endpoint is called, the server fails to validate the caller's existing permissions before granting elevated privileges. For detailed technical information, refer to the GitHub Security Advisory GHSA-x8hc-fqv3-7gwf.

Detection Methods for CVE-2026-33950

Indicators of Compromise

• Unexpected administrative accounts or sessions appearing in SignalK server logs
• Unauthorized access attempts to the /enableSecurity endpoint from external IP addresses
• Configuration changes to vessel routing or navigation parameters without authorized user activity
• Anomalous API requests to restricted endpoints from previously unknown sources

Detection Strategies

• Monitor HTTP access logs for requests to the /enableSecurity endpoint, particularly from unauthenticated sources
• Implement network intrusion detection rules to identify exploitation attempts targeting SignalK server endpoints
• Review SignalK server audit logs for unauthorized privilege escalation events or new administrator account creation
• Deploy application-layer monitoring to detect abnormal patterns in API request sequences

Monitoring Recommendations

• Enable detailed logging for all authentication and authorization events on SignalK server instances
• Configure alerts for any changes to administrative user accounts or security configurations
• Monitor network traffic to SignalK servers for unusual patterns or unauthorized access attempts
• Implement continuous security monitoring for marine IoT infrastructure components

How to Mitigate CVE-2026-33950

Immediate Actions Required

• Upgrade Signal K Server to version 2.24.0-beta.4 or later immediately
• Restrict network access to SignalK server instances using firewall rules until patching is complete
• Review server logs for any signs of exploitation or unauthorized administrative access
• Audit current administrative accounts and remove any unauthorized entries

Patch Information

The vulnerability has been patched in Signal K Server version 2.24.0-beta.4. Organizations should upgrade to this version or later to remediate the vulnerability. The patch information and release notes are available at the GitHub Release v2.24.0-beta.4.

For additional technical details regarding the security fix, consult the GitHub Security Advisory GHSA-x8hc-fqv3-7gwf.

Workarounds

• Implement network segmentation to isolate SignalK servers from untrusted networks
• Deploy a web application firewall (WAF) to block unauthorized requests to the /enableSecurity endpoint
• Restrict access to the SignalK server management interface to trusted IP addresses only
• Disable external network access to the SignalK server until the patch can be applied

# Example: Restrict access to SignalK server using iptables
# Allow only trusted management IP
iptables -A INPUT -p tcp --dport 3000 -s 192.168.1.100 -j ACCEPT
# Block all other access to SignalK port
iptables -A INPUT -p tcp --dport 3000 -j DROP