CVE-2025-66398
Critical · 9.6Signal K Server has Unauthenticated State Pollution leading to Remote Code Execution (RCE)
CVSS
9.6
EPSS
19.9%
Published
Jan 2, 2026
CISA due date
—
The record
An unauthenticated attacker can pollute the internal state (`restoreFilePath`) of the server via the `/skServer/validateBackup` endpoint. This allows the attacker to hijack the administrator's "Restore" functionality to overwrite critical server configuration files (e.g., `security.json`, `package.json`), leading to account takeover and Remote Code Execution (RCE).
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| npm | signalk-server | 0 | 2.19.0 |
Related vulnerabilities
- GHSA-w3x5-7c4c-66p9 Signal K Server has Unauthenticated State Pollution leading to Remote Code Execution (RCE) Same vulnerability
- GHSA-q59x-jc9f-gfqf Signal K Server: Server-Side Request Forgery via Remote Connection Endpoints Also affects signalk-server
- CVE-2026-41893 Signal K Server is a server application that runs on a central hub in a boat. Also affects signalk-server
- GHSA-vmfm-ch9h-5c7g Signal K Server's WebSocket Login Endpoint Lacks Rate Limiting (Credential Brute-Force) Also affects signalk-server
- GHSA-7gcj-phff-2884 Signal K Server has an Unauthenticated Regular Expression Denial of Service (ReDoS) via… Also affects signalk-server
- CVE-2026-39320 Signal K Server is a server application that runs on a central hub in a boat. Also affects signalk-server
- GHSA-cxj8-ggf2-p57c Signal K Server: OAuth Authorization Code Theft via Unvalidated Host Header in OIDC Flow Also affects signalk-server
- GHSA-gfmv-vh34-h2x5 Signal K Server: Unauthenticated Source Priorities Manipulation Also affects signalk-server