Concurrent Version System is a version control system that can record the history of your files. An array index error, leading to a heap-based buffer overflow, was found in the way CVS applied certain delta fragment changes from input files in the RCS format. If an attacker in control of a CVS repository stored a specially-crafted RCS file in that repository, and then tricked a remote victim into checking out a revision containing that file, it could lead to arbitrary code execution with the privileges of the CVS server process on the system hosting the CVS repository. Red Hat would like to thank Ralph Loader for reporting this issue. All users of cvs are advised to upgrade to this updated package, which contains a backported patch to correct this issue.