main/nginx: mitigate CVE-2021-3618
CVE-2021-3618 is an application layer protocol content confusion attack, affecting multiple applications.
According to redhat, nginx addressed this in hg:ec10718307991 or git:173f16f736c102 in mainline, but this has not been backported to a stable version yet.
Backport this fix ourselves.
Fixes #13737 (closed)
Edited by Kevin Daudt