This message was reported to full-disclosure http://lists.netsys.com/pipermail/full-disclosure/2004-November/029434.html It is possible to crash firefox with a few lines of HTML. This issue is being watched upstream by these bugs https://bugzilla.mozilla.org/show_bug.cgi?id=271716 https://bugzilla.mozilla.org/show_bug.cgi?id=271718
The Mozilla Software Foundation do not in general treat simple unexploitable crashes of a browser as a security issues. Removing security severity.
Fedora Core 3 is now maintained by the Fedora Legacy project for security updates only. If this problem is a security issue, please reopen and reassign to the Fedora Legacy product. If it is not a security issue and hasn't been resolved in the current FC5 updates or in the FC6 test release, reopen and change the version to match. Thank you!
Looks like this got fixed already by upstream.