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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2019-18668
• https://wordpress.org/plugins/currency-switcher-woocommerce/#developers
• https://wpvulndb.com/vulnerabilities/9936
• https://www.infigo.hr/en/critical-vulnerability-in-currency-switcher-for-woocommerce-n61