SAN FRANCISCO (KRON) — A cyber security company is warning Android users that more than 600 million Samsung phones may be exposed to backers.

Chicago-based cyber security company, Now Secure, discovered the security flaw in Samsung phones.

The vulnerability lives in the phone’s keyboard software, which can’t be deleted. The flaw potentially allows hackers to spy on anybody who uses a Galaxy phone.

That means hackers could eavesdrop on phone calls, possibly stealing data off the phone.

The vulnerability impacts the Samsung Galaxy “S” series smartphones. That includes the Galaxy S6, S5, S4 and S4 Mini.

Representatives with Samsung say they are aware of the security hole and will send out an update that will fix it in the coming days.

Until that update, cyber security experts are recommending not using public WiFi hotspots with the impacted phones.