qutebrowser before version 1.4.1 is vulnerable to a cross-site request forgery flaw that allows websites to access 'qute://*' URLs. A malicious website could exploit this to load a 'qute://settings/set' URL, which then sets 'editor.command' to a bash script, resulting in arbitrary code execution.
Created qutebrowser tracking bugs for this issue:
Affects: fedora-all [bug 1600289]
Qutebrowser 1.4.1 has been pushed to the stable repository of both F27 and F28 :-)
I close this bug since the issue is resolved.