TIO Networks, a bill-payment platform PayPal acquired over the summer, announced a security vulnerability may have affected the personal information of some 1.6 million customers, according to multiple media reports.

PayPal acquired TIO Networks in July for $238 million in its efforts to expand services to financially underserved consumers.

Last month, TIO Networks suspended operations after PayPay discovered the data breach. While PayPal said it has not found actual proof that data was stolen, it found enough evidence to treat the vulnerability as a data breach.

PayPal has since notified consumers and billers about the vulnerability.