A cryptograhic flaw in Magento 2.1 prior to 2.1.18, Magento 2.2 prior to 2.2.9, Magento 2.3 prior to 2.3.2 could be abused by an unauthenticated user to discover an invariant used in gift card generation.
github.com/FriendsOfPHP/security-advisories/blob/master/magento/product-community-edition/CVE-2019-7855.yaml
github.com/magento/magento2
magento.com/security/patches/magento-2.3.2-2.2.9-and-2.1.18-security-update-23
nvd.nist.gov/vuln/detail/CVE-2019-7855
web.archive.org/web/20220121051916/https://magento.com/security/patches/magento-2.3.2-2.2.9-and-2.1.18-security-update-23