CVE-2026-41893 Signal K Server's WebSocket Login Endpoint Lacks Rate Limiting (Credential Brute-Force)
Attackers can bypass HTTP rate limits via WebSocket to brute-force credentials, potentially taking over accounts on Signal K Server.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-41893?
CVE-2026-41893 is a high-severity vulnerability in signalk-server, published on 9 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Signal K Server is a server application that runs on a central hub in a boat. Prior to version 2.25.0, the HTTP login endpoints (POST /login and POST /signalk/v1/auth/login) are protected by express-rate-limit (default: 100 attempts per 10-minute window, configurable via HTTP_RATE_LIMITS). The WebSocket login path — sending {login: {username, password}} messages over an established WebSocket connection — calls app.securityStrategy.login() directly without any rate limiting. An attacker can bypass HTTP rate limiting entirely by opening a WebSocket connection and attempting unlimited password guesses at the speed bcrypt allows (~20 attempts/sec with 10 salt rounds). This issue has been patched in version 2.25.0.
Weakness: CWE-307
Which versions are affected by CVE-2026-41893?
2 open source packages ship an affected version, including signalk-server. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
signalk-server npm | All versions | 2.25.0 |
signalk-server npm | All versions | 2.25.0 |
Products include Signalk Signal K Server.
How do I fix CVE-2026-41893?
Upgrade signalk-server to 2.25.0 or later.
Is CVE-2026-41893 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-41893 exists.
Other vulnerabilities in signalk-server
- CVE-2026-23515 RCE - Command Injection in Signal K set-system-time plugin
- CVE-2025-66398 Signal K Server has Unauthenticated State Pollution leading to Remote Code Execution (RCE)
- CVE-2026-33950 signalk-server: Privilege Escalation by Admin Role Injection via /enableSecurity
- CVE-2025-68620 Signal K Server vulnerable to JWT Token Theft via WebSocket Enumeration and Unauthenticated Polling
- CVE-2026-39320 Signal K Server has an Unauthenticated Regular Expression Denial of Service (ReDoS) via WebSocket Subscription Paths
Sources
Also known as GHSA-vmfm-ch9h-5c7g.