When creating content with a very large title or description field, Plone can become unresponsive. Even if the content loads, it can be hard to edit or delete, because the UI is unwieldy.

The problem has been patched in plone.app.dexterity.

Another part of this problem has been patched in plone.app.contenttypes. See this advisory.

There are no known workarounds.

This problem was responsibly reported by Aldin Visnjic to the Plone/Zope Security Team. Thank you!

Note: The Plone/Zope Security team felt that the kind of fixes that were needed could be disruptive in corner cases if they were not careful. So they decided to develop the fixes publicly, giving the whole community the chance the review, and giving them the benefit from early feedback.