Mozilla Firefox before 30.0 and Thunderbird through 24.6 on OS X do not ensure visibility of the cursor after interaction with a Flash object and a DIV element, which makes it easier for remote attackers to conduct clickjacking attacks via JavaScript code that produces a fake cursor image.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.