Util/PHP/eval-stdin.php in PHPUnit starting with 4.8.19 and before 4.8.28, as well as 5.x before 5.6.3, allows remote attackers to execute arbitrary PHP code via HTTP POST data beginning with a <?php substring, as demonstrated by an attack on a site with an exposed /vendor folder, i.e., external access to the /vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php URI.

References

• https://nvd.nist.gov/vuln/detail/CVE-2017-9841
• sebastianbergmann/phpunit#1956
• sebastianbergmann/phpunit@284a69f
• https://security.gentoo.org/glsa/201711-15
• https://www.oracle.com/security-alerts/cpuoct2021.html
• http://web.archive.org/web/20170701212357/http://phpunit.vulnbusters.com/
• http://www.securityfocus.com/bid/101798
• http://www.securitytracker.com/id/1039812
• sebastianbergmann/phpunit#1955
• sebastianbergmann/phpunit@3aaddb1
• https://github.com/FriendsOfPHP/security-advisories/blob/master/phpunit/phpunit/CVE-2017-9841.yaml