# CVE-2026-33951: signalk-server: Unauthenticated Source Priorities Manipulation

> Remote attackers can modify trusted navigation data source priorities via an unauthenticated API endpoint, compromising marine navigation integrity.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Apr 2026
- **Updated:** 2 Apr 2026
- **Also known as:** GHSA-gfmv-vh34-h2x5

## What is CVE-2026-33951?

CVE-2026-33951 is a medium-severity missing authorization vulnerability in signalk-server, published on 2 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Signal K Server is a server application that runs on a central hub in a boat. Prior to version 2.24.0-beta.1, 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. This issue has been patched in version 2.24.0-beta.1.

Weakness: CWE-306 (Missing Authentication for Critical Functionality), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2026-33951?

2 open source packages ship an affected version, including signalk-server. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `signalk-server` | npm | All versions | 2.24.0-beta.1 |
| `signalk-server` | npm | All versions | 2.24.0-beta.1 |

Products: Signalk Signal K Server.

## How do I fix CVE-2026-33951?

Upgrade signalk-server to 2.24.0-beta.1 or later.

## Is CVE-2026-33951 being exploited?

There is no known exploitation of CVE-2026-33951 in the wild and no public exploit code.

## Other vulnerabilities in signalk-server

- [CVE-2026-23515](https://insights.sbomify.com/CVE-2026-23515/): RCE - Command Injection in Signal K set-system-time plugin (critical 10.0)
- [CVE-2025-66398](https://insights.sbomify.com/CVE-2025-66398/): Signal K Server has Unauthenticated State Pollution leading to Remote Code Execution (RCE) (critical 9.7)
- [CVE-2026-33950](https://insights.sbomify.com/CVE-2026-33950/): signalk-server: Privilege Escalation by Admin Role Injection via /enableSecurity (critical 9.4)
- [CVE-2025-68620](https://insights.sbomify.com/CVE-2025-68620/): Signal K Server vulnerable to JWT Token Theft via WebSocket Enumeration and Unauthenticated Polling (critical 9.1)
- [CVE-2026-41893](https://insights.sbomify.com/CVE-2026-41893/): Signal K Server's WebSocket Login Endpoint Lacks Rate Limiting (Credential Brute-Force) (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-33951 and fix it if it is affected.

What it is: CVE-2026-33951 is a medium-severity missing authorization vulnerability in signalk-server, published on 2 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-33951 in the wild and no public exploit code.

Affected packages and fixed versions:
- signalk-server (npm): affected all versions; fixed in 2.24.0-beta.1
- signalk-server (npm): affected all versions; fixed in 2.24.0-beta.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-33951/ (Markdown: https://insights.sbomify.com/CVE-2026-33951/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33951
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33951
- OSV: https://osv.dev/vulnerability/CVE-2026-33951

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33951/
Summaries are generated and may contain mistakes; the official description above is the record.