The "pingsender" executable used by the Firefox Health Report dynamically loads a system copy of libcurl, which an attacker could replace. This allows for privilege escalation as the replaced libcurl code will run with Firefox's privileges. Note: This attack requires an attacker have local system access and only affects OS X and Linux. Windows systems are not affected. This vulnerability affects Firefox < 57.
https://www.mozilla.org/security/advisories/mfsa2017-24/
https://bugzilla.mozilla.org/show_bug.cgi?id=1401339