New 1.8 patch releases are available.
You can get ruby-1.8.5-p231, ruby-1.8.6-p230 and ruby-1.8.7-p22 from "Release".
And, snapshot release of 1.9.0 is available.
You can get i386 and x64 version of ruby-1.9.0-2 from "Developping versions snapspots".
These releases contain the fixes of multiple vulnerabilities.