CVE-2026-34576 Postiz: SSRF in upload-from-url endpoint allows fetching internal resources and cloud metadata

Postiz is an AI social media scheduling tool. Prior to version 2.21.3, the POST /public/v1/upload-from-url endpoint accepts a user-supplied URL and fetches it server-side using axios.get with no SSRF protections. The only validation is a file extension check .png, .jpg, etc. which is trivially...