CVE-2026-41893

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

HIGH
7.5
CVSS Score
Published: May 9, 2026 at 07:12 PM UTC
Updated: July 24, 2026 at 07:20 PM UTC
1 product affected across 1 vendorSignal K Server

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Severity
HIGH7.5
Exploit prediction
EPSS 0.3%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.25.0
Affected range stops below 2.25.0, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/SignalK/signalk-server/security/advisories/GHSA-vmfm-ch9h-5c7g
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/SignalK/signalk-server/pull/2568
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/SignalK/signalk-server/releases/tag/v2.25.0

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-307

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