Vulnerability · Published May 9, 2026 · Assigned by GitHub_M
CVE-2026-41893Signal K Server's WebSocket Login Endpoint Lacks Rate Limiting (Credential Brute-Force)
High 8.7
In plain English
A high-severity security flaw in signalk-server from SignalK. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 26% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | signalk-server | 2.25.0 | GHSA-vmfm-ch9h-5c7g |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| SignalK | signalk-server | < 2.25.0 |
Weakness: CWE-307 · 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
References
- https://github.com/SignalK/signalk-server/security/advisories/GHSA-vmfm-ch9h-5c7g x_refsource_CONFIRM
- https://github.com/SignalK/signalk-server/pull/2568 x_refsource_MISC
- https://github.com/SignalK/signalk-server/commit/215d81eb700d5419c3396a0fbf23f2e246dfac2d x_refsource_MISC
- https://github.com/SignalK/signalk-server/releases/tag/v2.25.0 x_refsource_MISC