Apache CXF before 3.3.4 and 3.2.11 does not restrict the number of message attachments present in a given message. This leaves open the possibility of a denial of service type attack, where a malicious user crafts a message containing a very large number of message attachments. From the 3.3.4 and 3.2.11 releases, a default limit of 50 message attachments is enforced. This is configurable via the message property "attachment-max-count".
https://www.oracle.com/security-alerts/cpujan2020.html
https://www.oracle.com/security-alerts/cpuapr2020.html
https://www.oracle.com/security-alerts/cpuApr2021.html
http://cxf.apache.org/security-advisories.data/CVE-2019-12406.txt.asc