Mozilla Firefox before 48.0 does not properly set the LINKABLE and URI_SAFE_FOR_UNTRUSTED_CONTENT flags of about: URLs that are used for error pages, which makes it easier for remote attackers to conduct spoofing attacks via a crafted URL, as demonstrated by misleading text after an about:neterror?d= substring.
Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:NI:LA:N4.3/CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N