diff --git a/src/System.Private.CoreLib/shared/System/StringComparer.cs b/src/System.Private.CoreLib/shared/System/StringComparer.cs
index 527a452989e8..8d88ccaa9e2b 100644
--- a/src/System.Private.CoreLib/shared/System/StringComparer.cs
+++ b/src/System.Private.CoreLib/shared/System/StringComparer.cs
@@ -61,7 +61,7 @@ public static StringComparer Create(CultureInfo culture, CompareOptions options)
         {
             if (culture == null)
             {
-                throw new ArgumentException(nameof(culture));
+                throw new ArgumentNullException(nameof(culture));
             }
 
             return new CultureAwareComparer(culture, options);
diff --git a/tests/CoreFX/CoreFX.issues.rsp b/tests/CoreFX/CoreFX.issues.rsp
index 463c1e2ee9c4..a8293465592f 100644
--- a/tests/CoreFX/CoreFX.issues.rsp
+++ b/tests/CoreFX/CoreFX.issues.rsp
@@ -80,6 +80,9 @@
 # Test failure: https://github.com/dotnet/corefx/issues/39223
 -nomethod System.ComponentModel.TypeConverterTests.FontConverterTest.TestConvertFrom
 
+# Test failure: https://github.com/dotnet/coreclr/pull/26570
+-nomethod System.Tests.StringComparerTests.CreateCultureOptions_InvalidArguments_Throws
+
 # corefx tests need to be updated for changes to GetHashCode
 -nomethod System.Numerics.Tests.GenericVectorTests.GetHashCodeInt16
 -nomethod System.Numerics.Tests.GenericVectorTests.GetHashCodeInt32