CVE-2016-5699: Python

Medium severity, CVSS 6.1. EPSS: 9.9% chance of exploitation in the next 30 days.

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.

Affected products

• Python Python: up to and including 2.7.9; version 3.0 only; version 3.0.1 only; version 3.1.0 only; version 3.1.1 only; version 3.1.2 only; …

Published 2016-09-02. Last modified 2026-06-17.