Kirby is an open-source content management system. Prior to versions 4.9.0 and 5.4.0, the system API endpoint leaks license data and installed version to authenticated users. This issue has been patched in versions 4.9.0 and 5.4.0.

Affected: Packagist: getkirby/cms

### TL;DR

This vulnerability affects all Kirby sites that might have potential attackers in the group of authenticated Panel users.

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### Introduction

Missing authorization allows authenticated users to perform actions they are not intended to have access to.

The effects of missing authorization can include unauthorized access to sensitive information as well as unauthorized changes to content or system information.

### Impact

Kirby's user permissions control which user role is allowed to perform specific actions in the CMS. These permissions are defined for each role in the user blueprint (`site/blueprints/users/...`). The permissions control the authorization of user actions (with handling of model-specific authorization omitted here for brevity).

Kirby provides the `access.system` permission (among others) that controls access to the system area of the Kirby Panel. This area contains internal system information like the installed Kirby, plugin and server versions, security state and Kirby license. If the `access.system` permission is disabled for a user role, users of that role should not be able to access this internal system information. However it is also possible to access some system information via the `/api/system` REST API endpoint. In affected releases, the response of this endpoint for authenticated users contained the installed Kirby version and the status, type and code of the installed Kirby license. These values are considered sensitive informatio…