XStream before version 1.4.14 is vulnerable to Remote Code Execution.The vulnerability may allow a remote attacker to run arbitrary shell commands only by manipulating the processed input stream. Only users who rely on blocklists are affected. Anyone using XStream's Security Framework allowlist is not affected. The linked advisory provides code workarounds for users who cannot upgrade. The issue is fixed in version 1.4.14.

As mitigation for CVE-2020-1945 Apache Ant 1.10.8 changed the permissions of temporary files it created so that only the current user was allowed to access them. Unfortunately the fixcrlf task deleted the temporary file and created a new one without said protection, effectively nullifying the effort. This would still allow an attacker to inject modified source files into the build process.

It was found that xstream API version 1.4.10 before 1.4.11 introduced a regression for a previous deserialization flaw. If the security framework has not been initialized, it may allow a remote attacker to run arbitrary shell commands when unmarshalling XML or any supported format. e.g. JSON. (regression of CVE-2013-7285)