CVE-2026-43946

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.

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

Kodem intelligence

1. What is CVE-2026-43946? CVE-2026-43946 is a high-severity incorrect authorization vulnerability in fuxa-server (npm), affecting versions = 1.3.0. It is fixed in 1.3.1. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. Which versions of fuxa-server are affected by CVE-2026-43946? fuxa-server (npm) versions = 1.3.0 is affected.
3. Is there a fix for CVE-2026-43946? Yes. CVE-2026-43946 is fixed in 1.3.1. Upgrade to this version or later.
4. Is CVE-2026-43946 exploitable, and should I be worried? Whether CVE-2026-43946 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2026-43946 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2026-43946? Upgrade fuxa-server to 1.3.1 or later.