CVE-2025-66398: signalk-server · OS Command Injection
Affects signalk-serverSource CVE Database V5
Not known to be exploited · 19% EPSS · CVSS 9.7 Critical : upgrade to 2.19.0 as a priority.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 19.8% chance of exploitation in 30 days – higher than 97% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 2.19.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 1 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade signalk/signalk-server to 2.19.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
GitHubsignalk/signalk-serverpkg:github/signalk/signalk-serverOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
- Immediate upgrade of all SignalK signalk-server instances to version 2.19.0 or later to apply the official patch.
- Restrict network access to the /skServer/validateBackup endpoint by implementing firewall rules or network segmentation, allowing only trusted administrative hosts to communicate with the server.
- Implement strict monitoring and logging of access to the restore functionality and related endpoints to detect anomalous activity.
- Conduct regular integrity checks on critical configuration files (security.json, package.json) to detect unauthorized modifications.
- Employ application-layer firewalls or intrusion detection systems capable of detecting command injection patterns targeting the signalk-server.
- Educate maritime IT staff about the risks and ensure secure configuration management practices are followed.
- If upgrading immediately is not feasible, consider disabling the Restore functionality temporarily or applying custom input validation to the vulnerable endpoint as a stopgap measure.
Description
Signal K Server is a server application that runs on a central hub in a boat. Prior to version 2.19.0, 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). Version 2.19.0 patches this vulnerability.