plone.app.contenttypes has a Denial of Service in File Upload due to excessive filename length

Impact

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

Patches

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

• On Plone 6.2, upgrade to plone.app.contenttypes 5.0.1.
• On Plone 6.1, upgrade to plone.app.contenttypes 4.0.10.
• On Plone 6.0, upgrade to plone.app.contenttypes 3.0.12

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

Workarounds

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.