Andreas Beckmann debian reports:
openvswitch-pki creates the following world writable directories during installation:
drwx-wx-wx 2 root root 40 Aug 1 05:32 /var/lib/openvswitch/pki/controllerca/incoming drwx-wx-wx 2 root root 40 Aug 1 05:32 /var/lib/openvswitch/pki/switchca/incoming
Even if an ordinary local user cannot list the contents of the directory, he may correctly derive/guess filenames (unless they are exclusively $(mktemp)) and delete and replace files in there.
I don't know how openvswitch-pki works, how it uses this directory, what probelms could possibly arise out of this.
References: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=683665
Please note on Fedora 16 and 17 run the command:
/usr/bin/ovs-pki --force init
to create the directories.