python_scripts.py in Plone before 4.2.3 and 4.3 before beta 1 allows remote attackers to execute Python code via a crafted URL, related to createObject.
https://plone.org/products/plone/security/advisories/20121106/04
https://plone.org/products/plone-hotfix/releases/20121106
https://github.com/plone/Products.CMFPlone/blob/4.2.3/docs/CHANGES.txt