During the parsing of a ASN.1 sequence, a pointer in the linked list of asn1_sequence is not
initialized by asn1_get_sequence_of(). In case an error occurs during parsing of the list, a
situation is created where the uninitialized pointer is passed to polarssl_free().
This sequence can be triggered when a PolarSSL entity is parsing a certificate. So practically this
means clients when receiving a certificate from the server or servers in case they are actively
asking for a client certificate.