The existence of a specifically requested local file can be found due to the double firing of the "onerror" when the "source" attribute on a "<track>" tag refers to a file that does not exist if the source page is loaded locally. This vulnerability affects Firefox < 51.
{ "binaries": [ { "binary_name": "firefox", "binary_version": "51.0.1+build2-0ubuntu0.14.04.1" }, { "binary_name": "firefox-dev", "binary_version": "51.0.1+build2-0ubuntu0.14.04.1" }, { "binary_name": "firefox-globalmenu", "binary_version": "51.0.1+build2-0ubuntu0.14.04.1" }, { "binary_name": "firefox-mozsymbols", "binary_version": "51.0.1+build2-0ubuntu0.14.04.1" }, { "binary_name": "firefox-testsuite", "binary_version": "51.0.1+build2-0ubuntu0.14.04.1" } ], "availability": "No subscription required" }
{ "binaries": [ { "binary_name": "firefox", "binary_version": "51.0.1+build2-0ubuntu0.16.04.1" }, { "binary_name": "firefox-dev", "binary_version": "51.0.1+build2-0ubuntu0.16.04.1" }, { "binary_name": "firefox-globalmenu", "binary_version": "51.0.1+build2-0ubuntu0.16.04.1" }, { "binary_name": "firefox-mozsymbols", "binary_version": "51.0.1+build2-0ubuntu0.16.04.1" }, { "binary_name": "firefox-testsuite", "binary_version": "51.0.1+build2-0ubuntu0.16.04.1" } ], "availability": "No subscription required" }