gotify/server vulnerable to Cross-site Scripting in the application image file upload
ImpactThe XSS vulnerability allows authenticated users to upload .html files. With that, an attacker could execute client side scripts **if** another user opened a link, such as:An attacker could potentially take over the account of the user that clicked the link. Keep in mind, the Gotify UI won't natively expose such a malicious link, so an attacker has to get the user to open the malicious link in a context outside of Gotify.PatchesThe vulnerability has been fixed in version 2.2.2.WorkaroundsYou can block access to non image files via a reverse proxy in the `./image` directory.Referenceshttps://github.com/gotify/server/pull/534
https://github.com/gotify/server/pull/535Thanks to rickshang (aka 无在无不在) for discovering and reporting this bug.