XStream is a simple library to serialize objects to XML and back again. In
affected versions this vulnerability may allow a remote attacker to request
data from internal resources that are not publicly available only by
manipulating the processed input stream with a Java runtime version 14 to
8. 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](https://x-stream.github.io/security.html#framework), you will
have to use at least version 1.4.18.