There is 1 open security issue in bullseye.
1 issue left for the package maintainer to handle:
When PgBouncer is configured to use "cert" authentication, a man-in-the-middle attacker can inject arbitrary SQL queries when a connection is first established, despite the use of TLS certificate verification and encryption. This flaw affects PgBouncer versions prior to 1.16.1.
You can find information about how to handle this issue in the security team's documentation.