Several flaws were found in the processing of malformed web content. A web page containing malicious content could cause Thunderbird to crash or, potentially, execute arbitrary code with the privileges of the user running Thunderbird (CVE-2016-1952, CVE-2016-1954, CVE-2016-1957, CVE-2016-1960, CVE-2016-1961, CVE-2016-1974, CVE-2016-1964, CVE-2016-1966).
Multiple security flaws were found in the graphite2 font library shipped with Thunderbird. A web page containing malicious content could cause it to crash or, potentially, execute arbitrary code with the privileges of the user running Thunderbird (CVE-2016-1977, CVE-2016-2790, CVE-2016-2791, CVE-2016-2792, CVE-2016-2793, CVE-2016-2794, CVE-2016-2795, CVE-2016-2796, CVE-2016-2797, CVE-2016-2798, CVE-2016-2799, CVE-2016-2800, CVE-2016-2801, CVE-2016-2802).