As far as i can tell amber is lacking these security updates due to downstream changes in qemu:
https://lists.debian.org/debian-security-announce/2020/msg00019.html
https://lists.debian.org/debian-security-announce/2020/msg00068.html
https://lists.debian.org/debian-security-announce/2020/msg00134.html
https://lists.debian.org/debian-security-announce/2020/msg00139.html
https://lists.debian.org/debian-security-announce/2020/msg00167.html
(..., there's more)
See https://master.pureos.net/synchrotron/
qemu buster/updates amber-security 1:3.1+dfsg-8+deb10u8 1:3.1+dfsg-2pureos1 Requires manual merge of downstream changes with source.