diff --git a/tracer/src/Datadog.Trace/PlatformHelpers/AspNetCoreHttpRequestHandler.cs b/tracer/src/Datadog.Trace/PlatformHelpers/AspNetCoreHttpRequestHandler.cs
index 56453950f888..de5c419a77ff 100644
--- a/tracer/src/Datadog.Trace/PlatformHelpers/AspNetCoreHttpRequestHandler.cs
+++ b/tracer/src/Datadog.Trace/PlatformHelpers/AspNetCoreHttpRequestHandler.cs
@@ -43,14 +43,30 @@ public AspNetCoreHttpRequestHandler(
 
         public string GetDefaultResourceName(HttpRequest request)
         {
+            // Be defensive: in some edge cases the HttpRequest object may be null (e.g.,
+            // framework- or host-specific error paths). Avoid throwing and return a safe default.
+            if (request is null)
+            {
+                return "UNKNOWN /";
+            }
+
             string httpMethod = request.Method?.ToUpperInvariant() ?? "UNKNOWN";
 
-            string absolutePath = request.PathBase.HasValue
-                                      ? request.PathBase.ToUriComponent() + request.Path.ToUriComponent()
-                                      : request.Path.ToUriComponent();
+            string absolutePath;
+            try
+            {
+                absolutePath = request.PathBase.HasValue
+                                   ? request.PathBase.ToUriComponent() + request.Path.ToUriComponent()
+                                   : request.Path.ToUriComponent();
+            }
+            catch
+            {
+                // If anything goes wrong building the path, fall back to root
+                absolutePath = "/";
+            }
 
-            string resourceUrl = UriHelpers.GetCleanUriPath(absolutePath)
-                                           .ToLowerInvariant();
+            var cleanedPath = UriHelpers.GetCleanUriPath(absolutePath);
+            string resourceUrl = (cleanedPath ?? "/").ToLowerInvariant();
 
             return $"{httpMethod} {resourceUrl}";
         }
diff --git a/tracer/test/Datadog.Trace.Tests/PlatformHelpers/AspNetCoreHttpRequestHandlerTests.cs b/tracer/test/Datadog.Trace.Tests/PlatformHelpers/AspNetCoreHttpRequestHandlerTests.cs
index 91f41e9d8195..0ef19191950a 100644
--- a/tracer/test/Datadog.Trace.Tests/PlatformHelpers/AspNetCoreHttpRequestHandlerTests.cs
+++ b/tracer/test/Datadog.Trace.Tests/PlatformHelpers/AspNetCoreHttpRequestHandlerTests.cs
@@ -5,6 +5,8 @@
 
 #if !NETFRAMEWORK
 using Datadog.Trace.PlatformHelpers;
+using Datadog.Trace.Configuration;
+using Datadog.Trace.Logging;
 using FluentAssertions;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Internal;
@@ -16,6 +18,19 @@ public class AspNetCoreHttpRequestHandlerTests
     {
         public const string OriginalPath = "/somepath/Home/Index";
 
+        [Fact]
+        public void GetDefaultResourceName_ReturnsUnknownSlash_WhenRequestIsNull()
+        {
+            var handler = new AspNetCoreHttpRequestHandler(
+                DatadogLogging.GetLoggerFor<AspNetCoreHttpRequestHandlerTests>(),
+                "aspnet_core.request",
+                IntegrationId.AspNetCore);
+
+            var result = handler.GetDefaultResourceName(null);
+
+            result.Should().Be("UNKNOWN /");
+        }
+
         [Theory]
         [InlineData(null, "/somepath/Home/Index")]
         [InlineData("", "/somepath/Home/Index")]