(CNN) Verizon has confirmed the personal information of six-million customers was recently leaked online.
A cyber-security company named Upguard uncovered the issue.
They said it was caused by "human error."
Upguard alerted Verizon on June 13-- but the security hole was not closed until June 22.
Verizon said no loss or theft of customer information occurred.
Still -- Upguard advises Verizon customers to update their pin codes... And never use the same one twice.