CVE-2025-66398 SignalK CVE debrief

Who should care

Signal K Server administrators, security teams, and IT personnel responsible for maintaining boat central hubs should assess exposure and apply the patch to prevent potential attacks.

Why it matters

CVE-2025-66398 is a critical vulnerability in Signal K Server that allows unauthenticated attackers to hijack the 'Restore' functionality, potentially leading to account takeover and Remote Code Execution (RCE). Administrators should assess exposure, apply the patch, and monitor for suspicious activity.

• Potential account takeover by unauthenticated attackers.
• Possible Remote Code Execution (RCE) via overwriting critical server configuration files.
• Compromise of server integrity and confidentiality.
• Verification of server configuration file integrity is required.

Technical summary

CVE-2025-66398 is a critical vulnerability in Signal K Server versions prior to 2.19.0. An unauthenticated attacker can exploit the `/skServer/validateBackup` endpoint to pollute the internal state (`restoreFilePath`) of the server, allowing them to hijack the administrator's 'Restore' functionality. This can lead to account takeover and Remote Code Execution (RCE) by overwriting critical server configuration files.

Defensive priority

High priority for Signal K Server administrators and security teams.

Recommended defensive actions

• Assess exposure by checking if the Signal K Server version is prior to 2.19.0.
• Apply the patch by upgrading to Signal K Server version 2.19.0 or later.
• Monitor the `/skServer/validateBackup` endpoint for suspicious activity.
• Review and update server configuration files (e.g., `security.json`, `package.json`) for potential tampering.
• Verify server configuration file integrity.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The CVE record and NVD entry provide details on the vulnerability in Signal K Server versions prior to 2.19.0. An unauthenticated attacker can exploit the `/skServer/validateBackup` endpoint to hijack the administrator's 'Restore' functionality, potentially leading to account takeover and Remote Code Execution (RCE).

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.