Owncast is an open source, self-hosted, decentralized, single user live video streaming and chat server. The Owncast application exposes an administrator API at the URL "/api/admin". The "emoji/delete" endpoint of said API allows administrators to delete custom emojis, which are saved on disk. The `name` parameter is taken from the JSON request and directly appended to the filepath that points to the emoji to delete. By using path traversal sequences (../), attackers with administrative privileges can exploit this endpoint to delete arbitrary files on the system, outside of the emoji directory.