Puppet before 2.6.17 and 2.7.x before 2.7.18, and Puppet Enterprise before 2.5.2, allows remote authenticated users to read arbitrary files on the puppet master server by leveraging an arbitrary user's certificate and private key in a GET request.
https://github.com/puppetlabs/puppet/commit/c3c7462e4066bf3a563987a402bf3ddf278bcd87
https://github.com/puppetlabs/puppet/commit/10f6cb8969b4d5a933b333ecb01ce3696b1d57d4
https://euvd.enisa.europa.eu/vulnerability/EUVD-2012-3811
https://bugzilla.redhat.com/show_bug.cgi?id=839130
http://www.ubuntu.com/usn/USN-1506-1
http://www.debian.org/security/2012/dsa-2511
http://secunia.com/advisories/50014
http://puppetlabs.com/security/cve/cve-2012-3864/
http://lists.opensuse.org/opensuse-updates/2012-07/msg00036.html
http://lists.opensuse.org/opensuse-security-announce/2012-08/msg00006.html