CVE-2026-41893

High

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.

SeverityHigh
CVSS7.5
Exploit probability—
ProductSignalk Signal K Server
PublishedMay 9, 2026
First seenMay 9, 2026
Weakness typeCWE-307CWE-307

How to fix

Update
  • signalk signal_k_server2.25.0 or later
  • signalk-server2.25.0 or later

Affected products

ProductAffected versionsFixed in
signalk signal_k_serverv < 2.25.02.25.0
signalk-servernpmv < 2.25.02.25.0

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