A typo in the MISP ACLComponent access control configuration caused the ACL rule for the previewEventAttributes action to reference the permission string 'theming_enabled' (with a trailing asterisk) instead of the correct 'theming_enabled'. In the MISP ACL system, the array values define which role or permission grants access to a given controller action. The adjacent entry previewEventObjects correctly uses ['theming_enabled'], confirming the intended restriction. The malformed key 'theming_enabled' does not match any valid permission identifier, causing the access control check for previewEventAttributes to malfunction. Depending on the ACL evaluation logic, this could result in either unauthorized users gaining access to the previewEventAttributes endpoint (authorization bypass) or legitimate users being denied access (availability impact).
The previewEventAttributes endpoint exposes event attribute data within MISP so an authorization bypass could expose sensitive indicator and attribute data to users who should not have access.
The fix corrects the ACL permission key for the previewEventAttributes action from the malformed string 'theming_enabled*' to the correct 'theming_enabled', restoring the intended access control restriction so that only users holding the theming_enabled permission can invoke the endpoint, consistent with the adjacent previewEventObjects entry.