All log rules of the new firewall GUI do not have rate limiting. Therefore, it is very easy to generate hundreds of log messages a second which will fill the logs and consume disk space. This can be used as a DoS attack, so too much logging should be prohibited.
http://git.ipfire.org/?p=ipfire-2.x.git;a=commitdiff;h=3bb4bb3fa136224792e7dbbcf8b4f801a5565284