FUXA has an unauthenticated arbitrary tag value disclosure via /api/getTagValue
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:45sends requests withoutx-api-keytoauthJwt.verifyToken(req, res, next).server/api/jwt-helper.js:46-64creates a signed guest token when nox-access-tokenis provided:
if (!token) { token = getGuestToken(); }
and then populates req.userId / req.userGroups from that guest token.
server/api/command/index.js:76-105exposes/api/getTagValue.server/runtime/scripts/index.js:106-111returnstruewhen 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.