October CMS version prior to build 437 contains a Cross Site Scripting (XSS) vulnerability in the Media module and create folder functionality that can result in an Authenticated user with media module permission creating arbitrary folder name with XSS content. This attack appear to be exploitable via an Authenticated user with media module permission who can create arbitrary folder name (XSS). This vulnerability appears to have been fixed in build 437.

October CMS through 1.0.431 allows XSS by entering HTML on the Add Posts page.

October CMS through 1.0.428 does not prevent use of .htaccess in themes, which allows remote authenticated users to execute arbitrary PHP code by downloading a theme ZIP archive from /backend/cms/themes, and then uploading and importing a modified archive with two new files: a .php file and a .htaccess file. NOTE: the vendor says "I don't think [an attacker able to login to the system under an account that has access to manage/upload themes] is a threat model that we need to be considering.