Mozilla community member Philipp reported a memory safety bug present in Firefox 68 when 360 Total Security was installed. This bug showed evidence of memory corruption in the accessibility engine and we presume that with enough effort that it could be exploited to run arbitrary code. This vulnerability affects Firefox < 69, Thunderbird < 68.2, and Firefox ESR < 68.2.
https://www.mozilla.org/security/advisories/mfsa2019-35/
https://www.mozilla.org/security/advisories/mfsa2019-33/
https://www.mozilla.org/security/advisories/mfsa2019-25/