#xss

All link fields within the TYPO3 installation are vulnerable to Cross-Site Scripting as authorized editors can insert javascript commands by using the url scheme `javascript:`.

It has been discovered that link tags generated by typolink functionality in the website's frontend are vulnerable to cross-site scripting - values being assigned to HTML attributes have not been parsed correctly. A valid backend user account is needed to exploit this vulnerability. As second and separate vulnerability in the filelist module of the backend user interface has been referenced with this advisory as well. Error messages being shown after using a malicious name for renaming a file are not propery encoded, thus vulnerable to cross-site scripting. A valid backend user account is needed to exploit this vulnerability.

It has been discovered that TYPO3 is susceptible to session fixation. If a user authenticates while anonymous session data is present, the session id is not changed. This makes it possible for attackers to generate a valid session id, trick users into using this session id (e.g. by leveraging a different Cross-Site Scripting vulnerability) and then maybe getting access to an authenticated session.

Failing to properly validate the HTTP host-header TYPO3 CMS is susceptible to host spoofing. TYPO3 uses the HTTP host-header to generate absolute URLs in several places like 404 handling, http(s) enforcement, password reset links and many more. Since the host header itself is provided by the client it can be forged to any value, even in a name based virtual hosts environment. A blog post describes this problem in great detail.

Two Cross-Site Scripting vulnerabilities have been discovered in Alkacon's OpenCMS affecting version 16, which could allow a user: with sufficient privileges to create and modify web pages through the admin panel, can execute malicious JavaScript code, after inserting code in the `title` field. Another could having the roles of gallery editor or VFS resource manager will have the permission to upload images in the .svg format containing JavaScript code. The code will be executed the moment another user accesses the image.

It has been discovered that the output table listing in the “Files” backend module is vulnerable to cross-site scripting when a file extension contains malicious sequences. Access to the file system of the server - either directly or through synchronization - is required to exploit the vulnerability.

It has been discovered that t3:// URL handling and typolink functionality are vulnerable to cross-site scripting. Not only regular backend forms are affected but also frontend extensions which use the rendering with typolink.

It has been discovered that the output of field validation errors in the Form Framework is vulnerable to cross-site scripting.

Backend API configuration using Page TSconfig is vulnerable to arbitrary code execution and cross-site scripting. TSconfig fields of page properties in backend forms can be used to inject malicious sequences. Field tsconfig_includes is vulnerable to directory traversal leading to same scenarios as having direct access to TSconfig settings. A valid backend user account having access to modify values for fields `pages.TSconfig` and `pages.tsconfig_includes` is needed in order to exploit this vulnerability.

Failing to properly encode user input, frontend forms handled by the form framework (system extension “form”) are vulnerable to cross-site scripting.