CVE-2020-21524

There is a XML external entity (XXE) vulnerability in halo v1.1.3, The function of importing other blogs in the background(/api/admin/migrations/wordpress) needs to parse the xml file, but it is not used for security defense, This vulnerability can detect the intranet, read files, enable ddos attacks, etc. exp:https://github.com/halo-dev/halo/issues/423