Padding Oracle vulnerability in Apache Druid extension, druid-pac4j. This could allow an attacker to manipulate a pac4j session cookie. This issue affects Apache Druid versions 0.18.0 through 30.0.0. Since the druid-pac4j extension is optional and disabled by default, Druid installations not using the druid-pac4j extension are not affected by this vulnerability. While we are not aware of a way to meaningfully exploit this flaw, we nevertheless recommend upgrading to version 30.0.1 or higher which fixes the issue and ensuring you have a strong druid.auth.pac4j.cookiePassphrase as a precaution.