It is possible to inject malicious OGNL or MVEL scripts into the /context.json public endpoint. This was partially fixed in 1.5.1 but a new attack vector was found. In Apache Unomi version 1.5.2 scripts are now completely filtered from the input. It is highly recommended to upgrade to the latest available version of the 1.5.x release to fix this problem.
https://github.com/corsisechero/CVE-2020-13942byVulHub
https://github.com/advisories/GHSA-xp5j-wj4h-2jq9
https://github.com/hoanx4/apche_unomi_rce
https://github.com/yaunsky/Unomi-CVE-2020-13942
https://github.com/1135/unomi_exploit
https://github.com/eugenebmx/CVE-2020-13942
https://advisory.checkmarx.net/advisory/CX-2020-4284