diff --git a/src/NzbDrone.Api/Config/HostConfigModule.cs b/src/NzbDrone.Api/Config/HostConfigModule.cs
index c0e99d265..37821bfbe 100644
--- a/src/NzbDrone.Api/Config/HostConfigModule.cs
+++ b/src/NzbDrone.Api/Config/HostConfigModule.cs
@@ -42,6 +42,9 @@ namespace NzbDrone.Api.Config
                            .ValidIp4Address()
                            .NotListenAllIp4Address()
                            .When(c => c.BindAddress != "*");
+
+            SharedValidator.RuleFor(c => c.UrlBase)
+                           .ValidUrlBase();
         }
 
         private HostConfigResource GetHostConfig()
diff --git a/src/NzbDrone.Core/NzbDrone.Core.csproj b/src/NzbDrone.Core/NzbDrone.Core.csproj
index db97f7e3e..2f1bac1f2 100644
--- a/src/NzbDrone.Core/NzbDrone.Core.csproj
+++ b/src/NzbDrone.Core/NzbDrone.Core.csproj
@@ -84,7 +84,7 @@
       <SpecificVersion>False</SpecificVersion>
       <HintPath>..\packages\RestSharp.105.0.1\lib\net4\RestSharp.dll</HintPath>
     </Reference>
-      <Reference Include="CookComputing.XmlRpc, Version=2.5.0.0, Culture=neutral, processorArchitecture=MSIL">
+    <Reference Include="CookComputing.XmlRpc, Version=2.5.0.0, Culture=neutral, processorArchitecture=MSIL">
       <SpecificVersion>False</SpecificVersion>
       <HintPath>..\packages\xmlrpcnet.2.5.0\lib\net20\CookComputing.XmlRpcV2.dll</HintPath>
     </Reference>
@@ -997,4 +997,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>
\ No newline at end of file
diff --git a/src/NzbDrone.Core/Validation/RuleBuilderExtensions.cs b/src/NzbDrone.Core/Validation/RuleBuilderExtensions.cs
index ade8f810b..d8207ee76 100644
--- a/src/NzbDrone.Core/Validation/RuleBuilderExtensions.cs
+++ b/src/NzbDrone.Core/Validation/RuleBuilderExtensions.cs
@@ -62,5 +62,10 @@ namespace NzbDrone.Core.Validation
         {
             return ruleBuilder.WithState(v => NzbDroneValidationState.Warning);
         }
+
+        public static IRuleBuilderOptions<T, string> ValidUrlBase<T>(this IRuleBuilder<T, string> ruleBuilder)
+        {
+            return ruleBuilder.SetValidator(new RegularExpressionValidator(@"^(?!\/?https?://[-a-z0-9.]+)", RegexOptions.IgnoreCase)).WithMessage("Must be a valid URL path (ie: '/sonarr')");
+        }
     }
 }
\ No newline at end of file