Deserialization of Untrusted Data
XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream, if using the version out of the box with Java runtime version 14 to 8 or with JavaFX installed. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. XStream 1.4.18 uses no longer a blacklist by default, since it cannot be secured for general purpose.
CWE-502 - Deserialization of Untrusted Data
Deserialization of untrusted data vulnerabilities enable an attacker to replace or manipulate a serialized object, replacing it with malicious data. When the object is deserialized at the victim's end the malicious data is able to compromise the victim’s system. The exploit can be devastating, its impact may range from privilege escalation, broken access control, or denial of service attacks to allowing unauthorized access to the application's internal code and logic which can compromise the entire system.