The Joomla extension JMedia is vulnerable to a stored XSS vulnerability. Unsanitised SVG uploads served without nosniff, leading to stored/reflected XSS.
The Joomla extension JMedia is vulnerable to an SSRF vulnerability. Remote-URL download could target internal/reserved addresses.
The Joomla extension JMedia is vulnerable to an authenticated arbitrary file upload, leading to RCE. Executable uploads/writes possible (incl. polyglot filenames); chmod didn't strip execute bits.