XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability which may allow a remote attacker to occupy a thread that consumes maximum CPU time and will never return. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16.
https://x-stream.github.io/security.html#workaround
https://x-stream.github.io/CVE-2021-21348.html
https://www.oracle.com/security-alerts/cpuoct2021.html
https://www.oracle.com/security-alerts/cpujan2022.html
https://www.oracle.com//security-alerts/cpujul2021.html
https://www.debian.org/security/2021/dsa-5004
https://security.netapp.com/advisory/ntap-20210430-0002/
https://lists.debian.org/debian-lts-announce/2021/04/msg00002.html
https://github.com/x-stream/xstream/security/advisories/GHSA-56p8-3fh9-4cvq