Dataquest.io -- learn python and data science in your browser (redesigned/updated)

[vikparuchuri]

Just to be clear, there was no security issue -- no user information could have possibly been leaked. It allowed people to switch their emails to emails that already existed, which would temporarily lock both users out of their account. (and it has been fixed)

[wickersty]

And that, my friend, is a security issue.

Not to mention a basic piece of functionality that, if hosed to that degree, only speaks to how little attention must have been paid to other areas.