Coinbase denied a breach after an incident at analytics vendor Amplitude exposed some customers' contact information. The exchange says customer funds remain secure, but exposed contact details can still feed phishing and SIM swapping. Separate incidents at South Korean financial firms add to the concern.
The exchange denied suffering a security breach on Wednesday after an incident at an analytics vendor exposed some customers' contact information. In an Oct. 28 post on X, the exchange said the incident involved Amplitude, a third-party analytics provider, and affected a small subset of its customers.
Coinbase found no evidence of unauthorized access to its systems and said customer funds remained secure. It is notifying affected customers and regulators, but it has not disclosed how many people were involved or which contact details were compromised.
Unverified claims put the number above 70,000
The disclosure followed allegations circulating on X that attackers had obtained contact details belonging to more than 70,000 Coinbase users. Bitcoin News reports that the figure remains unverified.
Secondary accounts identified email addresses and telephone numbers as potentially compromised, according to Bitcoin News, although Coinbase has not independently confirmed those fields. No compromise of passwords, private keys, recovery phrases, or account balances has been reported.
Contact data still fuels attacks
Binance founder Changpeng Zhao said on X that criminals exploit compromised customer records for phishing, SIM swapping and social engineering. He recommended using separate email aliases and phone numbers for exchange accounts, replacing SMS authentication with passkeys or hardware security keys, and enabling withdrawal restrictions.
The Coinbase disclosure coincided with separate incidents involving South Korean exchange Bithumb, Daishin Securities and Mirae Asset Global Investments. Daishin confirmed that personal and financial information belonging to 38,490 customers had been exposed after suspicious activity detected on Oct. 17.
South Korean authorities launched investigations on Wednesday.
Third-party exposure puts Coinbase under scrutiny
The latest incident appears considerably narrower than a contractor-related episode uncovered in May 2025, when bribed customer-support personnel at Taskus accessed information belonging to 69,461 Coinbase users. Bitcoin News adds that its timing puts the exchange under scrutiny ahead of third-quarter earnings scheduled for Thursday, Oct. 29.
Sources: CryptoSlate, Bitcoin News
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