One of Apple's competitors in the mobile payment space sent out an email Wednesday telling users it has been breached, CNBC confirmed.

CurrentC, which is a mobile payment system backed by the Mercantile Exchange (MCX), sent out an email to its pilot users stating that an unauthorized third party had obtained email addresses of some of its users, the MCX confirmed to CNBC in an email statement.

Byers Market Newsletter Get breaking news and insider analysis on the rapidly changing world of media and technology right to your inbox. This site is protected by recaptcha

"Yes. Within the last 36 hours, we learned that unauthorized third parties obtained the e-mail addresses of some of our CurrentC pilot program participants and individuals who had expressed interest in the app. Many of these email addresses are dummy accounts used for testing purposes only. The CurrentC app itself was not affected," a spokesperson for MCX said in a statement.

"We have notified our merchant partners about this incident and directly communicated with each of the individuals whose email addresses were involved. We take the security of our users' information extremely seriously. MCX is continuing to investigate this situation and will provide updates as necessary," the statement said.

While CurrentC has not yet fully launched commercially, it has been in the spotlight recently because some of the retailers who are aligned with MCX, including CVS and Rite Aid, have disabled the technology in their stores that enables Apple Pay, CurrentC's rival.

IN-DEPTH

--- Cadie Thompson, CNBC