CVE 2015-3154
CRLF injection vulnerability in Zend\Mail (Zend_Mail) in Zend Framework before 1.12.12, 2.x before 2.3.8, and 2.4.x before 2.4.1 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via CRLF sequences in the header of an email.
See the
CVE page on Mitre.org
for more details.