CVE-2021-20328

Specific versions of the Java driver that support client-side field level
encryption (CSFLE) fail to perform correct host name verification on the
KMS server’s certificate. This vulnerability in combination with a
privileged network position active MITM attack could result in interception
of traffic between the Java driver and the KMS service rendering Field
Level Encryption ineffective. This issue was discovered during internal
testing and affects all versions of the Java driver that support CSFLE. The
Java async, Scala, and reactive streams drivers are not impacted. This
vulnerability does not impact driver traffic payloads with CSFLE-supported
key services originating from applications residing inside the AWS, GCP,
and Azure network fabrics due to compensating controls in these
environments. This issue does not impact driver workloads that don’t use
Field Level Encryption.