Mailvelope prior to 3.1.0 is vulnerable to a clickjacking attack against the settings page

Mailvelope prior to 3.1.0 is vulnerable to a clickjacking attack against the settings page. As the settings page is intended to be accessible from web applications, the browser's extension isolation mechanisms are disabled (web_accessible_resources). Mailvelope implements additional measures to prevent web applications from directly embedding the settings page, but this mechanism can be bypassed.