A malicious content author could upload a GPX file with a Javascript payload. The payload could then be executed by luring a legitimate user to view the file in a browser with support for GPX files. GPX is an XML-based format used to store GPS data. By default, Silverstripe CMS will no longer allow GPX files to be uploaded to the assets area.
A malicious content author could add arbitrary attributes to HTML editor shortcodes which could be used to inject a JavaScript payload on the front end of the site. The shortcode providers that ship with Silverstripe CMS have been reviewed and attribute allow lists have been implemented where appropriate to negate this risk.
Silverstripe silverstripe/assets through 1.10 allows XSS.
In SilverStripe through 4.5, files uploaded via Forms to folders migrated from Silverstripe CMS 3.x may be put to the default "/Uploads" folder instead. This affects installations which allowed upload folder protection via the optional silverstripe/secureassets module under 3.x. This module is installed and enabled by default on the Common Web Platform (CWP). The vulnerability only affects files uploaded after an upgrade to 4.x.
SilverStripe through 4.3.3 has incorrect access control for protected files uploaded via Upload::loadIntoFile(). An attacker may be able to guess a filename in silverstripe/assets via the AssetControlExtension.