Steam, the popular online gaming platform, experienced major unspecified issues that may have put millions of users' private information at risk.

The breach or malfunction was reported by users on Friday that forced users to access the accounts of complete strangers, placing private information such as home addresses, credit card numbers and more sensitive info at risk.

Doug Lombardi, Valve Corporation's vice president of marketing, told The Independent that the issue was resolved by Friday night.

"Steam is back up and running without any known issues. As a result of a configuration change earlier today, a caching issue allowed some users to randomly see pages generated for other users for a period of less than an hour," Mr Lombardi said in an email.

"This issue has since been resolved. We believe no unauthorized actions were allowed on accounts beyond the viewing of cached page information and no additional action is required by users."

Millions of users worldwide logged into Steam on Christmas Day only to realize that their homepage was written in several languages foreign to their own, Kotaku reports.

Steam Database, a community-run fansite, originally predicted that the problem was caused by caching issues.

"Valve is having caching issues allowing users to view things such as account information of other users," SteamDB wrote on Twitter. "Don't use Store for now."