Check untrusted users are not allowed to input dangerous HTML tags.

Problem/Motivation

In this Drupal application, untrusted roles (such as Anonymous or basic Authenticated users) may be assigned text formats that allow dangerous HTML tags or attributes (for example <script>, inline event handlers, or iframes), which can lead to XSS and content injection vulnerabilities across user-generated content.

Steps to reproduce

Proposed resolution

Add a new Security FitCheck plugin UntrustedHtmlInputCheck that:

• Inspects Drupal text format configuration and the roles allowed to use each format, focusing on untrusted roles like Anonymous and standard Authenticated users.
• Checks whether these formats permit dangerous HTML (or grant access to “Full HTML”/unfiltered HTML) for those roles.
• Marks the check as failing with FitWeight::High (or FitWeight::Critical if untrusted roles can use Full/Unfiltered HTML) and lists the affected formats and roles so administrators can restrict access or tighten allowed tags.

Remaining tasks

User interface changes

API changes

Data model changes