CVE-2026-33951 is a medium-severity missing authentication for critical function vulnerability in signalk-server (npm), affecting versions < 2.24.0-beta.1. It is fixed in 2.24.0-beta.1.
Summary The SignalK Server exposes an unauthenticated HTTP endpoint that allows remote attackers to modify navigation data source priorities. This endpoint, accessible via PUT /signalk/v1/api/sourcePriorities, does not enforce authentication or authorization checks and directly assigns user-controlled input to the server configuration. As a result, attackers can influence which GPS, AIS, or other sensor data sources are trusted by the system. The changes are immediately applied and persisted to disk, allowing the manipulation to survive server restarts. Affected Component File: src/serverroutes.ts Endpoint: PUT /signalk/v1/api/sourcePriorities (also accessible at /skServer/sourcePriorities) Lines: 1064-1076 Function: Source priorities configuration handler Vulnerable Code Vulnerability Characteristics Missing Authentication: The endpoint has zero authentication middleware, allowing unauthenticated access from any network-adjacent attacker. Direct Configuration Assignment: User-supplied request body is directly assigned to app.config.settings.sourcePriorities without validation or sanitization. Persistent Storage: Malicious configuration is written to disk via writeSettingsFile(), ensuring changes survive server restarts. Live Configuration Update: Changes take effect immediately via activateSourcePriorities(), affecting live navigation data processing. No Input Validation: No JSON schema validation, type checking, or field allowlisting is performed on the request body. Impact Navigation Data Manipulation: Attackers can modify source priorities to change which existing, active source's data is being used
A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.
CVE-2026-33951 has a CVSS score of 7.5 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (2.24.0-beta.1). Upgrading removes the vulnerable code path.
npm
signalk-server (< 2.24.0-beta.1)signalk-server → 2.24.0-beta.1 (npm)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-33951 is reachable in your applications. Explore open-source security for your team.
See if CVE-2026-33951 is reachable in your applications. Get a demo
Upgrade signalk-server to 2.24.0-beta.1 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-33951 is a medium-severity missing authentication for critical function vulnerability in signalk-server (npm), affecting versions < 2.24.0-beta.1. It is fixed in 2.24.0-beta.1. A critical operation is accessible without requiring any authentication.
CVE-2026-33951 has a CVSS score of 7.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
signalk-server (npm) versions < 2.24.0-beta.1 is affected.
Yes. CVE-2026-33951 is fixed in 2.24.0-beta.1. Upgrade to this version or later.
Whether CVE-2026-33951 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade signalk-server to 2.24.0-beta.1 or later.