The PayPal IPN utility 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 use of the PHP fsockopen function.
CVSS Score
5.8
EPSS Score
0.001
Published
2012-11-04