How safe is your kids' digital data at school?

As summer vacation winds down, new legislation is raising concern over digital privacy at school. Nationwide, only four states prohibit kids' personal information from being shared by schools with third party vendors, like marketers.

Common Sense Media founder and CEO Jim Steyer said until a couple of years ago, many schools weren't even aware this was happening.

"Because there were no laws about it -- school districts aren't that knowledgeable about it -- they were selling it to marketers, etc. so we started passing laws at Common Sense around the country, starting in California, to restrict the use of that data to only educational purposes," Steyer said Monday on "CBS This Morning."

That California law takes effect in January 2016 and prohibits practices including targeting advertising to minor students or their parents based on personal information, amassing students' information and disclosing students' personal information if the student's name is attached to that information.

Delaware is the latest state to have a law protecting the privacy of kindergarten through high school-aged students. Oregon and Delaware have similar laws and nine other states -- Maine, Maryland, Florida, Mississippi, Georgia, Hawaii, Iowa, North Carolina and Illinois -- are considering laws for student privacy.

Just two years ago, Steyer said, there were no states with such laws.

According to Common Sense Media, information at risk includes performance records, family finances, online searches and behavior records.

"What's happening is because everything is going online and because a lot of kids... are getting laptops and iPads in classrooms, people are getting accounts where personal information -- health, behavior, all sorts of personal, family information -- is stored," Steyer said.

Across the country, 95 percent of school districts use cloud services but only 25 percent inform parents of that usage, according to a Fordham University Law School study.

"The one thing I'd say to parents though is tech is here to stay in kids' education, and used properly, it can be great, but we have to protect kids' privacy," Steyer said.

But Steyer said his company, a non-profit organization that advocates for and educates families about technology, faced pushback for their efforts.

"The technology industry spent millions of dollars lobbying against us. They would like to have unfettered access to -- by the way, your (parents') personal information -- as well as your kids' information, so we started passing these laws ... and the momentum is moving in the right direction," Steyer said.