CentOS Errata and Bugfix Advisory 2015:0274 

Upstream details at : https://rhn.redhat.com/errata/RHBA-2015-0274.html

The following updated files have been uploaded and are currently 
syncing to the mirrors: ( sha256sum Filename ) 

i386:
71234f9406eca6a41884cbaaff642485e10e0a031e300e1d054453e9cfb14ff8  ruby-1.8.7.374-4.el6_6.i686.rpm
b3163be4b0290781509741fe40c3f31d590507101a8a49a874f52cc3481ebb0b  ruby-devel-1.8.7.374-4.el6_6.i686.rpm
ed32c82f71478c9ff251d81d48db568b90371e067b67090dc611018a80cdc32b  ruby-docs-1.8.7.374-4.el6_6.i686.rpm
f074916f420a394ff4f6e102dfbd0264896630817e70c25ae122cb4662b25cc5  ruby-irb-1.8.7.374-4.el6_6.i686.rpm
99c696d220f88578b9ac908c52d7c7d50fc1cde62f5b90beaff61a2cabb7d55b  ruby-libs-1.8.7.374-4.el6_6.i686.rpm
95043fecd149c116e7596fecdef5765e2518f38e56f192b73d5d7435acd3951a  ruby-rdoc-1.8.7.374-4.el6_6.i686.rpm
3e070909710e9329b92b570c6128057122d2b1c04a97a62a8ac8a47bc9e79ed7  ruby-ri-1.8.7.374-4.el6_6.i686.rpm
1d80cda61fc8cd6f4d65ce605197b71ed8d774d5006c702bee281988203636fb  ruby-static-1.8.7.374-4.el6_6.i686.rpm
bee5cf1fd558d263b3cafff8c1d28abf2fdfb64f84cf552002e2b30dce443f29  ruby-tcltk-1.8.7.374-4.el6_6.i686.rpm

x86_64:
760db1ec22721384125263dc7d4f8f5e74d6d6cb1867659e17e6a8fdbc5726b2  ruby-1.8.7.374-4.el6_6.x86_64.rpm
b3163be4b0290781509741fe40c3f31d590507101a8a49a874f52cc3481ebb0b  ruby-devel-1.8.7.374-4.el6_6.i686.rpm
0821dea5d7e3d79c9b8faa01275706d411f61a846bc78d94e305da06f46d6585  ruby-devel-1.8.7.374-4.el6_6.x86_64.rpm
542442bc6e620e6c11bd0ea9a49c0e1dc7e16ac57a0b76bd1f8b1543e43b0c1a  ruby-docs-1.8.7.374-4.el6_6.x86_64.rpm
e04c1fc17afdfd29e1e23d788c47715894b553cc90318e4146d3d93d65a0cf3a  ruby-irb-1.8.7.374-4.el6_6.x86_64.rpm
99c696d220f88578b9ac908c52d7c7d50fc1cde62f5b90beaff61a2cabb7d55b  ruby-libs-1.8.7.374-4.el6_6.i686.rpm
b473a43d5c201bf9706ab1cbe2d6ef0fc1a6042295e20753d8307326b2fce116  ruby-libs-1.8.7.374-4.el6_6.x86_64.rpm
93b3e1baf539d598efe1a1ab094e6718d10472947086ca7e89638615c8b57dbd  ruby-rdoc-1.8.7.374-4.el6_6.x86_64.rpm
f2d677239f26999f710bb228e57525a64ab0b95f3b9ec2e384daa1b5b1569a26  ruby-ri-1.8.7.374-4.el6_6.x86_64.rpm
e5cd12caa438960187e3c724592de30ff80cc9e14ebf9b3c5a0fe3ab9550ff6d  ruby-static-1.8.7.374-4.el6_6.x86_64.rpm
9dbe206d541870495944580e18247031fc0873f33b2711d19aa2ccaaed1b559c  ruby-tcltk-1.8.7.374-4.el6_6.x86_64.rpm

Source:
d59e8ddea5341b50b411253dd5b5c9975038a9b880a12d9675ebb4b7b71ec8e1  ruby-1.8.7.374-4.el6_6.src.rpm