I ran into a bit of an issue while setting up a new subversion server today. On that box we're running mod_security on all vhosts to add another layer of security to our web apps. I got everything configured with the the security, but when I was testing, I kept getting 403 errors when I attempted to get the files in anything other than a web browser.

After scratching my head for a while, I looked at the Apache logs, and noticed that mod_rewrite was causing the issue with lines like this:

I stumbled on Charl van Niekerk's entry on this. One of the comments suggested that the following is the bare minimum to run mod_security on a vhost running subversion:

This should be in the first directives in your mod_security call:

If you run a Subversion repository and have run into this issue, these security filters should help!