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.

The Recurly Client Python Library before 2.0.5, 2.1.16, 2.2.22, 2.3.1, 2.4.5, 2.5.1, 2.6.2 is vulnerable to a Server-Side Request Forgery vulnerability in the "Resource.get" method that could result in compromise of API keys or other critical resources.

The Recurly Client .NET Library before 1.0.1, 1.1.10, 1.2.8, 1.3.2, 1.4.14, 1.5.3, 1.6.2, 1.7.1, 1.8.1 is vulnerable to a Server-Side Request Forgery vulnerability due to incorrect use of "Uri.EscapeUriString" that could result in compromise of API keys or other critical resources.