CVE-2019-18668
An issue was discovered in the Currency Switcher addon before 2.11.2 for WooCommerce if a user provides a currency that was not added by the administrator. In this case, even though the currency does not exist, it will be selected, but a price amount will fall back to the default currency. This means that if an attacker provides a currency that does not exist and is worth less than this default, the attacker can eventually purchase an item for a significantly cheaper price.
Source: CVE-2019-18668