Impact

A malicious request can cause production log files to quickly fill up and thus result in the server running out of disk space.

Patches

The problem has been patched in the latest version of Discourse.

Workarounds

It is possible to temporarily work around this problem by reducing the client_max_body_size nginx directive. This can be done by adding the following lines to the container definition file:

run:
    - replace:
        global: true
        filename: /etc/nginx/conf.d/discourse.conf
        from: /client_max_body_size .*$/
        to: client_max_body_size 0.16m;

Note that the client_max_body_size will limit the size of uploads that can be uploaded directly to the server.