Python Improper Neutralization of CRLF Sequences in HTTP Headers (HTTP Response Splitting) Vulnerability - CVE-2016-5699
CRLF injection vulnerability in the HTTPConnection.putheader function in urllib2 and urllib in CPython (aka Python) before 2.7.10 and 3.x before 3.4.4 allows remote attackers to inject arbitrary HTTP headers via CRLF sequences in a URL.