This is a mod_ssl issue which only affects 2.x: http://issues.apache.org/bugzilla/show_bug.cgi?id=37791 2.0.x patch attached. It's a remotely-triggered NULL pointer dereference (so interesting only if you use a threaded MPM), affects server configurations with an SSL vhost configured with access control and a custom 400 errordocument; so this is rated "low".
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2006-0159.html