CVS (Concurrent Versions System) is an open-source network-transparent version control system. It contains both a client utility and a server.
Alen Zukich has discovered several serious security issues in CVS, including at least one buffer overflow (CAN-2005-0753), memory leaks and a NULL pointer dereferencing error. Furthermore when launching trigger scripts CVS includes a user controlled directory.
An attacker could exploit these vulnerabilities to cause a Denial of Service or execute arbitrary code with the permissions of the CVS pserver or the authenticated user (depending on the connection method used).
There is no known workaround at this time.
All CVS users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-util/cvs-1.11.20"