Twitter today revealed a bug in the Firefox browser that accidentally stored non-public files inside its cache, which normally stores information and files temporarily only. Those files stayed in the cache folder for as long as seven days, Twitter found.
The micro-blogging site says that Firefox cached these temporary files even after a user has logged out or left its platform. In a worst-case scenario, this would allow anyone to retrieve those pieces of information. This could happen if a user signed in to Twitter using a shared or public computer via Firefox and downloaded Twitter data archive or send a media file via Direct Message.
Twitter says it already fixed the problem by implementing changes to prevent Firefox from storing personal information in its cache folder moving forward. In a blog post, it says:
"We’re very sorry this happened. We recognize and appreciate the trust you place in us, and are committed to earning that trust every day."
Twitter also warned people that use shared or public computers to clear the browser's cache before signing out.