CVE-2026-41893
HIGHSignal K Server's WebSocket Login Endpoint Lacks Rate Limiting (Credential Brute-Force)
Title source: cnaDescription
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.
References (4)
Core 4
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/SignalK/signalk-server/security/advisories/GHSA-vmfm-ch9h-5c7g
X_Refsource_Misc x_refsource_misc
https://github.com/SignalK/signalk-server/pull/2568
X_Refsource_Misc x_refsource_misc
https://github.com/SignalK/signalk-server/commit/215d81eb700d5419c3396a0fbf23f2e246dfac2d
X_Refsource_Misc x_refsource_misc
https://github.com/SignalK/signalk-server/releases/tag/v2.25.0
Scores
CVSS v3
7.5
EPSS
0.0033
EPSS Percentile
24.4%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-307
Status
published
Products (3)
npm/signalk-server
0 - 2.25.0npm
signalk/signal_k_server
< 2.25.0
SignalK/signalk-server
< 2.25.0
Published
May 09, 2026
Tracked Since
May 10, 2026