Apache CXF before 3.3.4 and 3.2.11 provides all of the components that are required to build a fully fledged OpenId Connect service. There is a vulnerability in the access token services, where it does not validate that the authenticated principal is equal to that of the supplied clientId parameter in the request. If a malicious client was able to somehow steal an authorization code issued to another client, then they could exploit this vulnerability to obtain an access token for the other client.
https://www.tenable.com/blog/oracle-january-2020-critical-patch-update-contains-255-cves
https://www.oracle.com/security-alerts/cpuoct2020.html
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-2019-12419.txt.asc