Post body can break out of containing div element.

[dloser]

Since commit 2aa3799, one can generate an arbitrary amount of elements in a post.

Example code: [code][left]...[left][/code][/left]...[/left]oops

Example output (edited): <div class="bbcode_code"><pre><div>...<div></pre></div></div>...</div>oops

Here the </pre> effectively closes the inner <div> elements, leaving the outer </div> elements unmatched.

Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems.