CVE-2026-23515
📋 TL;DR
Signal K Server versions before 1.5.0 contain a command injection vulnerability in the set-system-time plugin that allows authenticated users with write permissions to execute arbitrary shell commands on the server. Unauthenticated users can also exploit this if server security is disabled, potentially leading to complete system compromise on affected marine navigation systems.
💻 Affected Systems
- Signal K Server
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing attackers to execute arbitrary commands as the server user, potentially gaining root access, installing malware, or disrupting critical marine navigation systems.
Likely Case
Authenticated users with write permissions could execute arbitrary commands, potentially compromising the server and connected marine systems.
If Mitigated
With proper authentication enabled and write permissions restricted, only trusted users could exploit, limiting impact to authorized personnel.
🎯 Exploit Status
Exploitation requires sending specially crafted WebSocket messages. Unauthenticated exploitation only possible when security is disabled on the Signal K server.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.5.0
Vendor Advisory: https://github.com/SignalK/signalk-server/security/advisories/GHSA-p8gp-2w28-mhwg
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Update Signal K Server to version 1.5.0 or later. 3. Restart the Signal K Server service. 4. Verify the update was successful.
🔧 Temporary Workarounds
Disable set-system-time plugin
allTemporarily disable the vulnerable plugin until patching can be completed
Edit Signal K Server configuration to remove or disable set-system-time plugin
Restart Signal K Server
Enable authentication
allEnsure authentication is enabled on Signal K Server to prevent unauthenticated exploitation
Configure Signal K Server security settings to require authentication
Restart Signal K Server
🧯 If You Can't Patch
- Disable the set-system-time plugin immediately
- Enable authentication and restrict write permissions to trusted users only
- Isolate Signal K Server from untrusted networks
- Implement network segmentation to limit potential lateral movement
🔍 How to Verify
Check if Vulnerable:
Check if Signal K Server version is below 1.5.0 and set-system-time plugin is enabledCheck Version:
Check Signal K Server web interface or configuration files for version informationVerify Fix Applied:
Verify Signal K Server version is 1.5.0 or higher and the set-system-time plugin has been updated📡 Detection & Monitoring
Log Indicators:
- Unusual shell command execution from Signal K Server process
- Suspicious WebSocket delta messages containing shell metacharacters
- Failed authentication attempts followed by command execution
Network Indicators:
- Unusual WebSocket traffic patterns to Signal K Server
- Suspicious payloads in WebSocket messages containing shell commands
SIEM Query:
Process execution from Signal K Server containing suspicious commands OR WebSocket traffic to Signal K Server with shell metacharacters