Puppet's certificate authority issued Puppet agent
certificates capable of impersonating the Puppet master.
Compromised or rogue puppet agents could therefore use
their certificates for MITM attacks (CVE-2011-3872).

Note: If you've set the 'certdnsnames' option in your
master's puppet.conf file merely installing the updated
packages is not sufficient to fix this problem. You need to
either pick a new DNS name for the master and reconfigure
all agents to use it or re-new certificates on all agents.

Please refer to the documentation in
/usr/share/doc/packages/puppet/puppetlabs-cve20113872-0.0.5
for detailed instructions and scripts.

Puppetlabs' site also provides more information:
http://puppetlabs.com/security/cve/cve-2011-3872/faq/
http://puppetlabs.com/blog/important-security-announcement-a
ltnames-vulnerability/

--

Directory traversal vulnerability in puppet allowed
unauthenticated remote attackers to upload x.509
certificate signing requests to arbitrary locations
(CVE-2011-3848)

Puppet was prone to several symlink attacks (CVE-2011-3870,
CVE-2011-3869, CVE-2011-3871)