A remote code execution vulnerability exists in Magento 2.2 prior to 2.2.10, Magento 2.3 prior to 2.3.3 or 2.3.2-p1. Dependency injection through Symphony framework allows service identifiers to be derived from user controlled data, which can lead to remote code execution.
As per the Magento Release 2.3.3, if you have already implemented the pre-release version of this patch (2.3.2-p1), it is highly recommended to promptly upgrade to 2.3.2-p2.

References

• https://nvd.nist.gov/vuln/detail/CVE-2019-8135
• https://github.com/FriendsOfPHP/security-advisories/blob/master/magento/product-community-edition/CVE-2019-8135.yaml
• https://magento.com/security/patches/magento-2.3.3-and-2.2.10-security-update