Postiz is an AI social media scheduling tool. Prior to 2.21.5, the /api/public/stream endpoint is vulnerable to SSRF. Although the application validates the initially supplied URL and blocks direct private/internal hosts, it does not re-validate the final destination after HTTP redirects. As a result, an attacker can supply a public HTTPS URL that passes validation and then redirects the server-side request to an internal resource.
https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-34w8-5j2v-h6ww
https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.5
https://github.com/gitroomhq/postiz-app/commit/30e8b777098157362769226d1b46d83ad616cb06