This update backports changes from the commons-collections 3.2.2 release which disable the deserialisation of the functors classes unless the system property org.apache.commons.collections.enableUnsafeSerialization is set to "true". This fixes a vulnerability in unsafe applications deserialising objects from untrusted sources without sanitising the input data. Classes considered unsafe are: CloneTransformer, ForClosure, InstantiateFactory, InstantiateTransformer, InvokerTransformer, PrototypeCloneFactory, PrototypeSerializationFactory and WhileClosure. For the oldstable distribution , this problem has been fixed in version 3.2.1-5+deb7u1.