In 32-bit versions of Firefox, the Adobe Flash plugin setting for "Enable Adobe Flash protected mode" is unchecked by default even though the Adobe Flash sandbox is actually enabled. The displayed state is the reverse of the true setting, resulting in user confusion. This could cause users to select this setting intending to activate it and inadvertently turn protections off. This vulnerability affects Firefox < 60.
https://www.mozilla.org/security/advisories/mfsa2018-11/
https://bugzilla.mozilla.org/show_bug.cgi?id=1451452