Plone 2.5 through 2.5.4 and 3.0 through 3.0.2 allows remote attackers to execute arbitrary Python code via network data containing pickled objects for the (1) statusmessages or (2) linkintegrity module, which the module unpickles and executes.
https://exchange.xforce.ibmcloud.com/vulnerabilities/38288
http://www.vupen.com/english/advisories/2007/3754
http://www.securityfocus.com/bid/26354
http://www.securityfocus.com/archive/1/483343/100/0/threaded
http://www.debian.org/security/2007/dsa-1405
http://secunia.com/advisories/27559
http://secunia.com/advisories/27530