Apache Unomi allows conditions to use OGNL and MVEL scripting which offers the possibility to call static Java classes from the JDK that could execute code with the permission level of the running Java process. This vulnerability affects all versions of Apache Unomi prior to 1.5.2.
View the template here CVE-2020-13942.yaml
References:
https://securityboulevard.com/2020/11/apache-unomi-cve-2020-13942-rce-vulnerabilities-discovered/