Mozilla Firefox before 49.0 does not properly restrict the scheme in favicon requests, which might allow remote attackers to obtain sensitive information via unspecified vectors, as demonstrated by a jar: URL for a favicon resource.
Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:HI:NA:N6.5/CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N