Vulnerability Instance

Mozilla security researcher moz_bug_r_a4 reported that
a form input control's type could be changed during the restoration of a
closed tab. An attacker could set an input control's text value to the
path of a local file whose location was known to the attacker. If the tab
was then closed and the victim persuaded to re-open it, upon restoring the
tab the attacker could use this vulnerability to change the input type to
file. Scripts in the page could then automatically submit
the form and steal the contents of the user's local file.