The Apache Software Foundation takes security issues very seriously. Apache Kafka® specifically offers security features and is responsive to issues around its features. If you have any concern around Kafka Security or believe you have uncovered a vulnerability, we suggest that you get in touch via the e-mail address firstname.lastname@example.org. In the message, try to provide a description of the issue and ideally a way of reproducing it. The security team will get back to you after assessing the description.
Note that this security address should be used only for undisclosed vulnerabilities. Dealing with fixed issues or general questions on how to use the security features should be handled regularly via the user and the dev lists. Please report any security problems to the project security address before disclosing it publicly.
The ASF Security team maintains a page with a description of how vulnerabilities are handled, check their Web page for more information.