The Recurly Client Ruby Library before 2.0.13, 2.1.11, 2.2.5, 2.3.10, 2.4.11, 2.5.4, 2.6.3, 2.7.8, 2.8.2, 2.9.2, 2.10.4, 2.11.3 is vulnerable to a Server-Side Request Forgery vulnerability in the "Resource#find" method that could result in compromise of API keys or other critical resources.

DL::dlopen in Ruby 1.8, 1.9.0, 1.9.2, 1.9.3, 2.0.0 before patchlevel 648, and 2.1 before 2.1.8 opens libraries with tainted names.

The Fiddle::Handle implementation in ext/fiddle/handle.c in Ruby before 2.0.0-p648, 2.1 before 2.1.8, and 2.2 before 2.2.4, as distributed in Apple OS X before 10.11.4 and other products, mishandles tainting, which allows context-dependent attackers to execute arbitrary code or cause a denial of service (application crash) via a crafted string, related to the DL module and the libffi library. NOTE: this vulnerability exists because of a CVE-2009-5147 regression.

RubyGems 2.0.x before 2.0.16, 2.2.x before 2.2.4, and 2.4.x before 2.4.7 does not validate the hostname when fetching gems or making API requests, which allows remote attackers to redirect requests to arbitrary domains via a crafted DNS SRV record, aka a "DNS hijack attack."