Dawid Golunski reported the nginx web server packages in Debian
suffered from a privilege escalation vulnerability (www-data to root)
due to the way log files are handled. This security update changes
ownership of the /var/log/nginx directory root. In addition,
/var/log/nginx has to be made accessible to local users, and local
users may be able to read the log files themselves local until the
next logrotate invocation.