Craft CMS Stored Cross-Site Scripting Vulnerability in Entry Type Names

A stored cross-site scripting vulnerability has been identified in Craft CMS versions 5.0.0-RC1 prior to 5.8.21. The issue arises because Entry Type names are not properly sanitized before being displayed in the Entry Types list, allowing for the injection of malicious scripts.

Impact

Exploitation of this vulnerability allows for stored cross-site scripting, where injected scripts are executed in the context of the user viewing the Entry Types list.

Reproduction

To reproduce this vulnerability, log in as an admin user with 'allowAdminChanges' enabled in production. Navigate to the Entry Types settings page, create a new Entry Type, and enter a name that includes a script injection, such as an image tag with an 'onerror' event. After saving the Entry Type, the injected script will execute when the Entry Types table is rendered.

Remediation

Users can upgrade to Craft CMS version 5.8.22 or later to address this vulnerability.