CVE-2021-29946
Ports that were written as an integer overflow above the bounds of a 16-bit integer could have bypassed port blocking restrictions when used in the Alt-Svc header. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88. Date published : 2021-06-24 https://bugzilla.mozilla.org/show_bug.cgi?id=1698503