diff --git a/.github/workflows/labeler.yml b/.github/workflows/labeler.yml
index 057208eda328..0127be633202 100644
--- a/.github/workflows/labeler.yml
+++ b/.github/workflows/labeler.yml
@@ -9,6 +9,6 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/labeler@v4
+    - uses: actions/labeler@v5
       with:
         repo-token: "${{ secrets.GITHUB_TOKEN }}"
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.StubGenerator/StubVisitor.cs b/csharp/extractor/Semmle.Extraction.CSharp.StubGenerator/StubVisitor.cs
index 57a1c823fc12..983175f4c17a 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp.StubGenerator/StubVisitor.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp.StubGenerator/StubVisitor.cs
@@ -534,6 +534,9 @@ private void StubParameters(ICollection<IParameterSymbol> parameters)
                 case RefKind.In:
                     stubWriter.Write("in ");
                     break;
+                case RefKind.RefReadOnlyParameter:
+                    stubWriter.Write("ref readonly ");
+                    break;
                 default:
                     stubWriter.Write($"/* TODO: {parameter.RefKind} */");
                     break;
@@ -884,4 +887,4 @@ public override void VisitProperty(IPropertySymbol symbol)
         if (explicitInterfaceImplementations.Length == 0)
             StubProperty(symbol, null);
     }
-}
\ No newline at end of file
+}
diff --git a/csharp/extractor/Semmle.Extraction.Tests/StubGenerator.cs b/csharp/extractor/Semmle.Extraction.Tests/StubGenerator.cs
index 598ff77ca25b..ea60c60bad61 100644
--- a/csharp/extractor/Semmle.Extraction.Tests/StubGenerator.cs
+++ b/csharp/extractor/Semmle.Extraction.Tests/StubGenerator.cs
@@ -42,7 +42,7 @@ public void StubGeneratorMethodTest()
         // Setup
         const string source = @"
 public class MyTest {
-    public int M1(string arg1) { return 0;}
+    public int M1(string arg1) { return 0; }
 }";
 
         // Execute
@@ -56,6 +56,26 @@ public class MyTest {
         Assert.Equal(expected, stub);
     }
 
+    [Fact]
+    public void StubGeneratorRefReadonlyParameterTest()
+    {
+        // Setup
+        const string source = @"
+public class MyTest {
+    public int M1(ref readonly Guid guid) { return 0; }
+}";
+
+        // Execute
+        var stub = GenerateStub(source);
+
+        // Verify
+        const string expected = @"public class MyTest {
+public int M1(ref readonly Guid guid) => throw null;
+}
+";
+        Assert.Equal(expected, stub);
+    }
+
     private static string GenerateStub(string source)
     {
         var st = CSharpSyntaxTree.ParseText(source);