HTTP fallback is a vulnerability in websites. It can be solved by using HSTS, or partially solved with secure cookies and redirecting to https. If a browser di

HTTP fallback is a vulnerability in websites. It can be solved by using HSTS, or partially solved with secure cookies and redirecting to https. If a browser disobeys these principles and uses HTTP anyway, that's a serious vulnerability. Same if a phone downgrades to insecure stuff.