Gateways/Gateway.php in Heartland & Global Payments PHP SDK before 2.0.0 does not enforce SSL certificate validations.
github.com/globalpayments/php-sdk
github.com/globalpayments/php-sdk/compare/1.3.3...2.0.0
github.com/globalpayments/php-sdk/pull/8
github.com/globalpayments/php-sdk/pull/8/commits/c86e18f28c5eba0d6ede7d557756d978ea83d3c9
github.com/globalpayments/php-sdk/releases/tag/2.0.0
nvd.nist.gov/vuln/detail/CVE-2019-20455
winterdragon.ca/global-payments-vulnerability