firefox: certificate verification bypass

Security researcher Muneaki Nishimura discovered a flaw in the Mozilla’s
HTTP Alternative Services implementation. If an Alt-Svc header is
specified in the HTTP/2 response, SSL certificate verification can be
bypassed for the specified alternate server. As a result of this,
warnings of invalid SSL certificates will not be displayed and an
attacker could potentially impersonate another site through a
man-in-the-middle (MTIM), replacing the original certificate with their own.