The Linux kernel 4.9.x before 4.9.233, 4.14.x before 4.14.194, and 4.19.x before 4.19.140 has a use-after-free because skcd->no_refcnt was not considered during a backport of a CVE-2020-14356 patch. This is related to the cgroups feature.
bugzilla.redhat.com/show_bug.cgi?id=1868453
cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.194
cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.140
cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.233
git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.14.y&id=82fd2138a5ffd7e0d4320cdb669e115ee976a26e
lists.debian.org/debian-lts-announce/2020/10/msg00032.html
lists.debian.org/debian-lts-announce/2020/10/msg00034.html
security.netapp.com/advisory/ntap-20201001-0004/
www.spinics.net/lists/stable/msg405099.html