FUXA is a web-based Process Visualization (SCADA/HMI/Dashboard) software. Version 1.3.0 has an authorization bypass in the /api/getTagValue endpoint allows unauthenticated access to tag values when the referenced script does not exist. Version 1.3.1 patches the issue.

Affected: npm: fuxa-server

### Summary An authorization bypass in the /api/getTagValue endpoint allows unauthenticated access to tag values when the referenced script does not exist.

### Details The issue is caused by the combination of these code paths:

- `server/api/apikeys/verify-api-or-token.js:45` sends requests without `x-api-key` to `authJwt.verifyToken(req, res, next)`. - `server/api/jwt-helper.js:46-64` creates a signed guest token when no `x-access-token` is provided: `if (!token) { token = getGuestToken(); }` and then populates `req.userId` / `req.userGroups` from that guest token. - `server/api/command/index.js:76-105` exposes `/api/getTagValue`. - `server/runtime/scripts/index.js:106-111` returns `true` when the referenced script does not exist: `if (!script) { return true; }`

As a result, an unauthenticated request reaches `/api/getTagValue` as `guest`, and the authorization check is bypassed because `isAuthorisedByScriptName()` returns `true` when `sourceScriptName` is omitted or does not match a real script. The endpoint then returns arbitrary tag values by ID.

### PoC

Requests to /api/getTagValue without authentication could succeed when the authorization logic evaluated a non-existent sourceScriptName as authorized.