The REST interface in Cisco Spark 2015-07-04 allows remote attackers to bypass intended access restrictions and create arbitrary user accounts via unspecified web requests, aka Bug ID CSCuv72584.
The Cisco Spark application 2015-07-04 for mobile operating systems does not properly verify X.509 certificates from SSL servers, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate, aka Bug IDs CSCut36742 and CSCut36844.