Coinbase has said a security incident at Amplitude, a third-party analytics provider, affected contact data belonging to a "small subset" of its customers, while stressing that the exchange itself had not been breached. "Coinbase has not had a data breach," the company's support account said in a tweet on Tuesday night. "Amplitude, an analytics vendor, experienced a security incident which impacted a small subset of Coinbase customer contact data, among other Amplitude customers."