Typemill is a flat-file, Markdown-based CMS designed for informational documentation websites. A reflected Cross-Site Scripting (XSS) exists in the login error view template `login.twig` of versions 2.19.1 and below. The `username` value can be echoed back without proper contextual encoding when authentication fails. An attacker can execute script in the login page context. This issue has been fixed in version 2.19.2.
Typemill v1.5.3 was discovered to contain an arbitrary file upload vulnerability via the upload function. This vulnerability allows attackers to execute arbitrary code via a crafted PHP file.