kiwitcms vulnerable to stored XSS via unrestricted files upload

Kiwi TCMS is an open source test management system for both manual and automated testing. Kiwi TCMS allows users to upload attachments to test plans, test cases, etc. Earlier versions of Kiwi TCMS had introduced upload validators in order to prevent potentially dangerous files from being uploaded. The upload validation checks were not robust enough which left the possibility of an attacker to circumvent them and upload a potentially dangerous file. Exploiting this flaw, a combination of files could be uploaded so that they work together to circumvent the existing Content-Security-Policy and allow execution of arbitrary JavaScript in the browser. This issue has been patched in version 12.3.