A vulnerability was found in Linux Kernel where in the spk_ttyio_receive_buf2() function, it would dereference spk_ttyio_synth without checking whether it is NULL or not, and may lead to a NULL-ptr deref crash.
https://www.debian.org/security/2021/dsa-4843
https://security.netapp.com/advisory/ntap-20210625-0004/
https://lists.debian.org/debian-lts-announce/2021/02/msg00018.html
https://bugzilla.redhat.com/show_bug.cgi?id=1919900