Location bar continues displaying wyciwyg URI and resource URI if user tries to navigate to it manually
Announced: January 26, 2016
Reporter: Jordi Chancel
Fixed in: Firefox 44
Security researcher Jordi Chancel reported two issues involving addressbar spoofing.
The second flaw is a « low » rated security issue affecting Desktop Firefox. In this attack, when a URL which is invalid for an internal protocol is pasted into the addressbar, the addressbar contents may be manipulated to show the location of an arbitrary website instead of the one currently loaded. This issue is mitigated by the protocol being prepended to the displayed URL, making the address less likely to be confused with the appended URL.
Vulnerability demonstration (video):