The default configuration for cURL and libcurl before 7.42.1 sends custom HTTP headers to both the proxy and destination server, which might allow remote proxy servers to obtain sensitive information by reading the header contents.
https://support.apple.com/kb/HT205031
https://kc.mcafee.com/corporate/index?page=content&id=SB10131
http://www.ubuntu.com/usn/USN-2591-1
http://www.securitytracker.com/id/1032233
http://www.securityfocus.com/bid/74408
http://www.oracle.com/technetwork/topics/security/cpuoct2015-2367953.html
http://www.oracle.com/technetwork/topics/security/cpujan2016-2367955.html
http://www.oracle.com/technetwork/topics/security/bulletinjan2016-2867206.html
http://www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html
http://www.debian.org/security/2015/dsa-3240
http://lists.opensuse.org/opensuse-updates/2015-05/msg00017.html
http://lists.apple.com/archives/security-announce/2015/Aug/msg00001.html
http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10743