Either that, or every company has woefully underpaid/incompetent IT people
It's this one. Cox Communications, one of the largest telecommunications companies in the US with $11 billion in revenue, recently patched a bug on their self-serve portal that allowed anyone to access any customer's profile. The bug was that server requests weren't being authenticated. If you entered the right info into the URL bar you'd be given a page with anyone's customer info. No login needed.