telepathy-idle before 0.1.15 does not verify (1) that the issuer is a trusted CA, (2) that the server hostname matches a domain name in the subject's Common Name (CN), or (3) the expiration date of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.
https://bugs.freedesktop.org/show_bug.cgi?id=63810
http://www.ubuntu.com/usn/USN-1821-1
http://www.securityfocus.com/bid/59474
http://www.openwall.com/lists/oss-security/2013/04/24/5
http://secunia.com/advisories/53361
http://lists.opensuse.org/opensuse-updates/2013-06/msg00052.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-May/104397.html