Silverstripe History XSS Vulnerability

A cross-site scripting vulnerability has been discovered in the CMS page history tab.

This vulnerability can only be exploited if a user with CMS access has posted malicious or unescaped HTML into any of the text fields on a page, and if the “compare mode” option is selected. The HTML will be embedded into the page unescaped.

This has been resolved by performing the text comparison in a HTML friendly way.