Several security vulnerabilities have been corrected in unbound, a validating, recursive, caching DNS resolver. Support for the unbound DNS server has been resumed, the sources can be found in the unbound1.9 source package.
CVE-2020-12662
Unbound has Insufficient Control of Network Message
Volume, aka an "NXNSAttack" issue. This is triggered by random
subdomains in the NSDNAME in NS records.
CVE-2020-12663
Unbound has an infinite loop via malformed DNS answers received from
upstream servers.
CVE-2020-28935
Unbound contains a local vulnerability that would allow for a local symlink
attack. When writing the PID file Unbound creates the file if it is not
there, or opens an existing file for writing. In case the file was already
present, it would follow symlinks if the file happened to be a symlink
instead of a regular file.
1.9.0-2+deb10u2~deb9u1