There is 1 open security issue in buster.
1 issue left for the package maintainer to handle:
The miekg Go DNS package before 1.1.25, as used in CoreDNS before 1.6.6 and other products, improperly generates random numbers because math/rand is used. The TXID becomes predictable, leading to response forgeries.
You can find information about how to handle this issue in the security team's documentation.