Oracle Linux: CVE-2021-39150: ELSA-2021-3956: xstream security update (IMPORTANT)

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.
A flaw was found in xstream, a simple library used to serialize objects to XML and back again. This flaw allows a remote attacker to request data from internal resources that are not publicly available by manipulating the processed input stream with Java runtime versions 14 to 8. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.