It is important to note that the flaw is exploitable by attackers only in one of the following scenarios:
A representative from Mozilla has clarified that the Android Firefox browser vulnerability has been fixed in Firefox for Android v24, released on September 17th. Sebastián Guerrero has found anyway a way to exploit the vulnerability remotely and decided, also in this case, to responsibly disclose it to Mozilla.
“However, to protect the most sensitive information, apps can place data in a separate location called internal storage, a private folder for each app that even the user is prevented from accessing directly (unless the device is rooted). The most significant threat from this vulnerability is that the secured location for Firefox is also accessible, which means a hacker will have access to cookies, login credentials, bookmarks, and anything else Mozilla think should be kept safely tucked away.” states Androidpolice blog.
The colleagues at The Hacker News reached Guerrero, following an useful series of answers and questions on the Android Android Firefox browser vulnerability: