The urllib and urllib2 modules in Python 2.x before 2.7.2 and 3.x before 3.2.1 process Location headers that specify redirection to file: URLs, which makes it easier for remote attackers to obtain sensitive information or cause a denial of service (resource consumption) via a crafted URL, as demonstrated by the file:///etc/passwd and file:///dev/zero URLs.
https://www.djangoproject.com/weblog/2011/sep/10/127/
https://www.djangoproject.com/weblog/2011/sep/09/
https://bugzilla.redhat.com/show_bug.cgi?id=737366
https://bugzilla.redhat.com/show_bug.cgi?id=690560
http://www.ubuntu.com/usn/USN-1613-2
http://www.ubuntu.com/usn/USN-1613-1
http://www.ubuntu.com/usn/USN-1596-1
http://www.ubuntu.com/usn/USN-1592-1
http://www.mandriva.com/security/advisories?name=MDVSA-2011:096
http://support.apple.com/kb/HT5002
http://securitytracker.com/id?1025488
http://secunia.com/advisories/51040
http://secunia.com/advisories/51024
http://secunia.com/advisories/50858
http://openwall.com/lists/oss-security/2011/09/15/5
http://openwall.com/lists/oss-security/2011/09/13/2
http://openwall.com/lists/oss-security/2011/09/11/1
http://openwall.com/lists/oss-security/2011/03/28/2
http://openwall.com/lists/oss-security/2011/03/24/5
http://lists.opensuse.org/opensuse-security-announce/2011-05/msg00005.html
http://lists.apple.com/archives/Security-announce/2011//Oct/msg00003.html
http://hg.python.org/cpython/rev/b2934d98dac1/
http://hg.python.org/cpython/rev/96a6c128822b/
http://hg.python.org/cpython/file/b2934d98dac1/Misc/NEWS