# CVE-2026-25228: SignalK Server path traversal in applicationData API

Source: https://junglewise.ai/threats/cve-2026-25228-signalk-server-path-traversal-in-applicationdata-api  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-02-02. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-25228 · Severity: low · CVSS 3.1 · Published 2026-02-02

SignalK Server is a marine navigation data aggregation platform used on vessels to centralize sensor and instrument data. On Windows systems, an authenticated user can read, write, and list arbitrary files outside the intended application data directory by exploiting a path traversal flaw in the file API. This allows exposure of sensitive configuration files, credentials, and other system data stored on the server.

Technologies: [signalk-server (npm)](https://junglewise.ai/threats/technologies/signalk-server). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-25228 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-25228 being exploited in the wild.

**How severe is CVE-2026-25228?** Low severity, with a CVSS score of 3.1, published 2 February 2026.

**Which products and versions are affected?** signalk-server (npm) SEMVER:introduced=0,fixed=2.20.3.

**Is there a fix for CVE-2026-25228?** Yes. signalk-server (npm): upgrade to 2.20.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-25228 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-25228?** Check whether you run signalk-server (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- signalk-server (npm): upgrade to 2.20.3 or later

  ```sh
  npm install signalk-server@2.20.3
  ```


## Technical details

A path traversal vulnerability exists in SignalK Server's applicationData API handler, specifically in the validateAppId() function. The function validates the appid parameter but only blocks forward slashes (/), not backslashes (\), which are treated as directory separators on Windows. Attackers who have valid authentication credentials can craft API requests using backslash-based traversal sequences (e.g., `..\..\..\`) to escape the intended applicationData directory and access arbitrary files. The vulnerability requires authentication and is platform-specific to Windows; Linux is unaffected. The fix involves validating both slash types and using path normalization to ensure resolved paths remain within the intended directory.

## Affected products

- SignalK SignalK Server <=2.20.2

## Identifiers

- CVE-2026-25228
- GHSA-vrhw-v2hw-jffx

## Timeline

- 2026-02-02: disclosed
- 2026-02-03: patched: Fixed in version 2.20.3

## References

- [https://github.com/SignalK/signalk-server/security/advisories/GHSA-vrhw-v2hw-jffx](https://github.com/SignalK/signalk-server/security/advisories/GHSA-vrhw-v2hw-jffx)

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