curl and libcurl before 7.50.1 do not check the client certificate when choosing the TLS connection to reuse, which might allow remote attackers to hijack the authentication of the connection by leveraging a previously created connection with a different client certificate.
http://lists.opensuse.org/opensuse-updates/2016-09/msg00011.html
http://lists.opensuse.org/opensuse-updates/2016-09/msg00094.html
http://rhn.redhat.com/errata/RHSA-2016-2575.html
http://rhn.redhat.com/errata/RHSA-2016-2957.html
https://access.redhat.com/errata/RHSA-2018:3558
https://security.gentoo.org/glsa/201701-47
https://www.tenable.com/security/tns-2016-18
http://www.debian.org/security/2016/dsa-3638
http://www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html
http://www.securitytracker.com/id/1036537