If your browser supports it, drag this bookmarklet to your bookmarks or favorites bar.

Your MEGA master key is supposed to be a secret, but MEGA or anyone else with access to your computer can easily find it without you noticing.

How it works

Once you have installed the bookmarklet, log into MEGA. Clicking the button will show you something like this:

The MEGA web site stores your secret master key in the local storage area of your web browser where any code running on your computer, in your browser, or on MEGA can easily retrieve it. While MEGApwn simply displays enough information to prove the correct key has been recovered, similar code could just as easily send your master key to anywhere on the Internet, including back to MEGA.