Unauthenticated Access Vulnerability in Signal K Server by Signal K
CVE-2025-66398

9.7CRITICAL

Key Information:

Vendor

Signalk

Status
Signalk-server
Vendor
CVE Published:
1 January 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2025-66398?

Signal K Server, a crucial application that serves as a central hub for maritime operations, harbors a vulnerability allowing unauthenticated attackers to manipulate the internal state via the /skServer/validateBackup endpoint. This weakness enables the attacker to exploit the server's 'Restore' functionality, leading to the potential overwrite of sensitive server configuration files, such as security.json and package.json. Consequently, this flaw provides a pathway for account takeover and Remote Code Execution (RCE). To mitigate these risks, users are advised to upgrade to version 2.19.0, where this vulnerability has been addressed.

Affected Version(s)

signalk-server < 2.19.0

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

cve-2025-66398
Created by joshuavanderpoll

References

https://github.com/SignalK/signalk-server/security/adviso...
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https://github.com/SignalK/signalk-server/releases/tag/v2...
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CVSS V3.1

Score:
9.7
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Changed

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.