CVE-2026-41893CWE-307

Signal K Server's WebSocket Login Endpoint Lacks Rate Limiting (Credential Brute-Force)

High · published May 9, 2026

CVSS v4.0
8.7
EPSS
1%
Percentile
42.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.7 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
EPSS
0.00509 · 42.5th percentile
Weakness
CWE-307 · Improper Restriction of Excessive Authentication Attempts
Published
2026-05-09T19:12Z
EPSS history
Timeline
  • 09 MAY 19:12Z
    Signal K Server's WebSocket Login Endpoint Lacks Rate Limiting (Credential Brute-Force)
    cvelistv5