7PK - Security Features
The add-on installation feature in Mozilla Firefox before 40.0.3 and Firefox ESR 38.x before 38.2.1 allows remote attackers to bypass an intended user-confirmation requirement by constructing a crafted data: URL and triggering navigation to an arbitrary http: or https: URL at a certain early point in the installation process.
CWE-254 - Security Features
Security features are integrated into the application infrastructure to protect its resources and the trusted environment against a known exploit, threat, or vulnerability. However, flawed, disabled, or absent security features expose the application to a variety of attacks. This is a multidimensional vulnerability with broad potential impact. It can lead to defacement, confidentiality compromise, system takeover, etc.