Crypto exchange Gemini has warned users to monitor their accounts for unusual activity after it confirmed that around 15,000 of its customers might be affected by a breach of its banking partner.

As reported by Bleeping Computer, Gemini began contacting affected customers last month to tell them that its unnamed automated clearing house provider had been breached. It informed the California Office of Attorney General last Thursday.

According to Gemini, “an unauthorized actor gained access to an internal collaboration tool on the bank partner’s system, which may have resulted in the potential disclosure of certain transactional data between June 3 and June 7, 2024.”

As a result, “a subset of some Gemini customers’ banking information was potentially impacted as part of the incident.,” the exchange added.

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This impacted information seemingly includes customer names, as well as the bank account and routing numbers they provided to Gemini for transferring funds.

However, the company stresses that other sensitive information such as dates of birth, home and email addresses, social security numbers, phone numbers, and passwords weren’t compromised. It also says that Gemini account information and systems are safe.

Gemini claims its banking partner has launched an investigation and notified the authorities. The exchange said, “Although we notified the customers involved out of an abundance of caution, our analysis found no evidence of customer impact.”

Customers have been advised to obtain a new bank account number, monitor their account statements for any unusual activity, and enable multi-factor authentication.

Protos has reached out to Gemini seeking comment on the banking partner leak.