On behalf of the Plone Foundation I'd like to draw your attention to a
security announcement that was published a few minutes ago.
This is a pre-announcement only, it does not contain any vulnerability
details. Your sites are a safe today as they were yesterday. However,
we are giving you advance warning that a patch is upcoming and
recommending that you plan a maintenance period for your sites to
coincide with the full announcement next week.
You can feel free to ask more questions on the plone-users mailing list
or in the #plone IRC channel about details and how to protect yourself,
but it is important to make a plan for this now. If you know you can't
install the fix at the time of release next week it would be a good idea
to plan the best time to have it installed with your administrators,
otherwise your site is potentially at risk from opportunistic hackers.