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.
Exploitability
AV:NAC:HPR:NUI:RScope
S:UImpact
C:NI:NA:H5.3/CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:HResource Management
Serialization