It is possible for a user with posting rights to the blog to make a post with an incredibly long title. The edit form sets a restriction of 48 characters however this is not double checked in edit_actions.php, thus allowing a user to submit a post with a longer title by accessing edit_actions.php directly.

A url such as this will probably do the job:

http://yoursite/blogs/admin/edit_actions.php?action=post&post_category=1&post_url=http://bbc.co.uk&post_title=insert_long_title_here

Hardly a show stopper but it is potentially very irritating for those of us with shared blogs.