PHP through 7.1.11 enables potential SSRF in applications that accept an fsockopen or pfsockopen hostname argument with an expectation that the port number is constrained. Because a :port syntax is recognized, fsockopen will use the port number that is specified in the hostname argument, instead of the port number in the second argument of the function.
http://www.securityfocus.com/bid/97178
http://www.securitytracker.com/id/1038158
https://bugs.php.net/bug.php?id=74216
https://bugs.php.net/bug.php?id=75505
https://github.com/php/php-src/commit/bab0b99f376dac9170ac81382a5ed526938d595a
Source: MITRE
Published: 2017-03-27
Updated: 2018-02-26
Type: CWE-918
Base Score: 5.8
Vector: AV:N/AC:M/Au:N/C:P/I:P/A:N
Impact Score: 4.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 7.4
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N
Impact Score: 4
Exploitability Score: 2.8
Severity: HIGH