Long back I spotted a Directory Traversal bug in Heroku.
“Heroku is a cloud platform is a cloud application platform – a new way of building and deploying web apps.. Heroku was acquired by Salesforce.com in 2010”
They were quite quick and fixed it without delays
Later they even started their hall of fame page and included my name there 🙂
https://www.heroku.com/policy/security-hall-of-fame
https://www.heroku.com/policy/security-hall-of-fame