---
id: "GHSA-7wpf-ch8f-5f4x"
kind: "vulnerability"
aliases: ["GHSA-7wpf-ch8f-5f4x"]
title: "signalk-server has SSRF via absolute signalk.appIcon URL in the app store icon fetcher"
severity: "medium"
cvss: 4.2
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "signalk-server", "fixed": ["2.34.0"], "affected": ">= 2.28.0-beta.2, < 2.34.0", "ecosystem": "npm"}]
ecosystems: ["npm"]
tags: ["cwe-918", "marine", "npm", "package", "self-hosted", "signalk-server"]
not_affected_if: ["default-config"]
published_at: "2026-10-30T22:57:37+00:00"
first_seen_at: "2026-10-30T23:02:03+00:00"
updated_at: "2026-10-30T23:02:44+00:00"
sources: [{"source": "ghsa", "url": "https://github.com/advisories/GHSA-7wpf-ch8f-5f4x", "first_seen_at": "2026-10-30T23:02:03+00:00"}]
---

# signalk-server has SSRF via absolute signalk.appIcon URL in the app store icon fetcher

signalk-server fetches the icon URL a plugin declares in its package, and accepts absolute http(s) URLs as-is and follows redirects. A malicious plugin listed in the app store can make the server request internal or cloud metadata addresses and store any image response as the plugin icon, which is then shown in the admin UI.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- npm:signalk-server affected >= 2.28.0-beta.2, < 2.34.0 fixed 2.34.0

## How to check

- Check the installed version with `npm ls signalk-server` or the server's package.json; affected versions are `>= 2.28.0-beta.2` and `< 2.34.0`.
- Look for `signalk.appIcon` values that are absolute URLs in installed plugin package.json files.

## Fix

- `signalk-server` `2.34.0`

## Timeline

- 2026-10-30T23:02:03+00:00 ghsa https://github.com/advisories/GHSA-7wpf-ch8f-5f4x

## Documents

- [advisory] Maintainer's advisory: api.github.com https://api.github.com/repos/SignalK/signalk-server/security-advisories/GHSA-7wpf-ch8f-5f4x
- [advisory] Maintainer's advisory: github.com https://github.com/SignalK/signalk-server/security/advisories/GHSA-7wpf-ch8f-5f4x
- [fix] Patch: github.com https://github.com/SignalK/signalk-server/commit/535104f655304c697d535252da397948e5101dc6
- [fix] Patch: github.com https://github.com/SignalK/signalk-server/commit/7eeae00ac4aee5f04e21e3ff9527f57823e65a4d
- [fix] Release: github.com https://github.com/SignalK/signalk-server/releases/tag/v2.34.0

## From the sources

### Summary

The app store icon code (`dist/appstore/icon-probe.js` around line 200 and `icon-bytes.js` around line 138) resolves a plugin's declared `signalk.appIcon`. Relative paths are pinned to the CDN, but an absolute http(s) URL is used as-is: the server fetches it, follows redirects, and stores any `image/*` response as the plugin's icon, which is then served to the admin UI. Unrelated to GHSA-q59x-jc9f-gfqf.

### Affected

signalk-server 2.33.0 (latest).

### Reproduction

The real dist modules driven directly, Docker with `--network none`; a local "internal" service on 127.0.0.1 logs requests:

```
[CONTROL relative] declared=../../icon.png
  resolved=null
  internal-service hits: []  stored: null
[ATTACK absolute] declared=http://127.0.0.1:35013/latest/meta-data/iam
  resolved=http://127.0.0.1:35013/latest/meta-data/iam
  internal-service hits: ["GET /latest/meta-data/iam"]  stored: .../icon-bytes/evil-plugin@1.0.0.png (70 bytes)
[ATTACK redirect] declared=http://127.0.0.1:35013/redir
  internal-service hits: ["GET /redir","GET /internal-secret-via-redirect.png"]  stored: .../icon-bytes/evil-plugin@1.0.0.png (70 bytes)
```

The modules were tested directly rather than through a full running server.

### Impact

Anyone who can get a plugin listed in the app store (publishing an npm package with the signalk keywords) can make every signalk-server that browses the app store send requests to internal addresses on the vessel network and to cloud metadata endpoints. Responses with an image content type are stored and served back to the user.

### Suggested fix

Only accept relative icon paths resolved against the CDN (or an https allowlist of known hosts), do not follow redirects to other hosts, and reject private, loopback and link-local addresses after resolution.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_