CVE 2015-2727
Mozilla Firefox 38.0 and Firefox ESR 38.0 allow user-assisted remote attackers to read arbitrary files or execute arbitrary JavaScript code with chrome privileges via a crafted web site that is accessed with unspecified mouse and keyboard actions. NOTE: this vulnerability exists because of a CVE-2015-0821 regression.
See the
CVE page on Mitre.org
for more details.