CVE-2026-41893

The record

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.

Affected packages

Related vulnerabilities

• GHSA-vmfm-ch9h-5c7g Signal K Server's WebSocket Login Endpoint Lacks Rate Limiting (Credential Brute-Force) Same vulnerability
• GHSA-q59x-jc9f-gfqf Signal K Server: Server-Side Request Forgery via Remote Connection Endpoints 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
• GHSA-x8hc-fqv3-7gwf Signal K Server: Privilege Escalation by Admin Role Injection via /enableSecurity Also affects signalk-server
• GHSA-qh3j-mrg8-f234 Signal K Server: Arbitrary Prototype Read via `from` Field Bypass Also affects signalk-server