There is 1 open security issue in buster.
1 issue left for the package maintainer to handle:
In Zsh before 5.8, attackers able to execute commands can regain privileges dropped by the --no-PRIVILEGED option. Zsh fails to overwrite the saved uid, so the original privileges can be restored by executing MODULE_PATH=/dir/with/module zmodload with a module that calls setuid().
You can find information about how to handle this issue in the security team's documentation.