Git before 2.10.5, 2.11.x before 2.11.4, 2.12.x before 2.12.5, 2.13.x before 2.13.6, and 2.14.x before 2.14.2 uses unsafe Perl scripts to support subcommands such as cvsserver, which allows attackers to execute arbitrary OS commands via shell metacharacters in a module name. The vulnerable code is reachable via git-shell even without CVS support.
In case you do not rely on the commands offered by the "-cvs" subpackage (for example "git cvsserver" or "git cvsimport") on RHEL or RHSCL, you can uninstall the git "-cvs" subpackage.