PayPal Payments Standard PHP Library before 20120427 does not verify that the server hostname matches a domain name in the subject's Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate, related to intentional disabling of certificate-validation checks through a "FALSE" value.

PayPal Payments Standard PHP Library 20120427 does not verify that the server hostname matches a domain name in the subject's Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate, related to misinterpretation of a certain TRUE value.