diff --git a/src/Prowlarr.Api.V1.Test/Indexers/NewznabControllerFixture.cs b/src/Prowlarr.Api.V1.Test/Indexers/NewznabControllerFixture.cs
new file mode 100644
index 000000000..34974476c
--- /dev/null
+++ b/src/Prowlarr.Api.V1.Test/Indexers/NewznabControllerFixture.cs
@@ -0,0 +1,18 @@
+using FluentAssertions;
+using Microsoft.AspNetCore.Http;
+using NUnit.Framework;
+using NzbDrone.Api.V1.Indexers;
+
+namespace Prowlarr.Api.V1.Test.Indexers
+{
+    public class NewznabControllerFixture
+    {
+        [TestCase("/api/v1/indexer/12/newznab", true)]
+        [TestCase("/12/api", false)]
+        [TestCase("/api/v1/indexer/12/download", false)]
+        public void should_only_allow_extended_search_parameters_on_prowlarr_newznab_route(string path, bool expected)
+        {
+            NewznabController.SupportsExtendedSearchParameters(new PathString(path)).Should().Be(expected);
+        }
+    }
+}
diff --git a/src/Prowlarr.Api.V1.Test/Prowlarr.Api.V1.Test.csproj b/src/Prowlarr.Api.V1.Test/Prowlarr.Api.V1.Test.csproj
index eec930286..72a865158 100644
--- a/src/Prowlarr.Api.V1.Test/Prowlarr.Api.V1.Test.csproj
+++ b/src/Prowlarr.Api.V1.Test/Prowlarr.Api.V1.Test.csproj
@@ -7,6 +7,7 @@
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\NzbDrone.Core\Prowlarr.Core.csproj" />
+    <ProjectReference Include="..\Prowlarr.Api.V1\Prowlarr.Api.V1.csproj" />
     <ProjectReference Include="..\NzbDrone.Test.Common\Prowlarr.Test.Common.csproj" />
     <ProjectReference Include="..\Prowlarr.Http\Prowlarr.Http.csproj" />
   </ItemGroup>
diff --git a/src/Prowlarr.Api.V1/AssemblyInfo.cs b/src/Prowlarr.Api.V1/AssemblyInfo.cs
new file mode 100644
index 000000000..59dc537b5
--- /dev/null
+++ b/src/Prowlarr.Api.V1/AssemblyInfo.cs
@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Prowlarr.Api.V1.Test")]
diff --git a/src/Prowlarr.Api.V1/Indexers/NewznabController.cs b/src/Prowlarr.Api.V1/Indexers/NewznabController.cs
index cde49b789..82b0b1353 100644
--- a/src/Prowlarr.Api.V1/Indexers/NewznabController.cs
+++ b/src/Prowlarr.Api.V1/Indexers/NewznabController.cs
@@ -58,6 +58,11 @@ public NewznabController(IndexerFactory indexerFactory,
         [HttpGet("{id:int}/api")]
         public async Task<IActionResult> GetNewznabResponse(int id, [FromQuery] NewznabRequest request)
         {
+            if (!SupportsExtendedSearchParameters(Request.Path))
+            {
+                request.searchMode = null;
+            }
+
             var requestType = request.t;
             request.source = Request.GetSource();
             request.server = Request.GetServerUrl();
@@ -206,6 +211,12 @@ public async Task<IActionResult> GetNewznabResponse(int id, [FromQuery] NewznabR
             }
         }
 
+        internal static bool SupportsExtendedSearchParameters(PathString path)
+        {
+            return path.Value?.StartsWith("/api/v1/indexer/", StringComparison.OrdinalIgnoreCase) == true &&
+                   path.Value.EndsWith("/newznab", StringComparison.OrdinalIgnoreCase);
+        }
+
         [HttpGet("/api/v1/indexer/{id:int}/download")]
         [HttpGet("{id:int}/download")]
         public async Task<object> GetDownload(int id, string link, string file)