diff --git a/RELEASE.md b/RELEASE.md
new file mode 100644
index 0000000000..cbb948b320
--- /dev/null
+++ b/RELEASE.md
@@ -0,0 +1,3 @@
+Release type: minor
+
+Update `extensions/mask_errors.py` to handle pre-execution errors and execution errors separately.
diff --git a/strawberry/extensions/mask_errors.py b/strawberry/extensions/mask_errors.py
index c2ecb0a707..292b73abc9 100644
--- a/strawberry/extensions/mask_errors.py
+++ b/strawberry/extensions/mask_errors.py
@@ -1,8 +1,7 @@
 from collections.abc import Iterator
-from typing import Any, Callable
+from typing import Callable
 
 from graphql.error import GraphQLError
-from graphql.execution import ExecutionResult
 
 from strawberry.extensions.base_extension import SchemaExtension
 
@@ -34,30 +33,29 @@ def anonymise_error(self, error: GraphQLError) -> GraphQLError:
             original_error=None,
         )
 
-    # TODO: proper typing
-    def _process_result(self, result: Any) -> None:
-        if not result.errors:
-            return
-
+    def _process_errors(self, errors: list[GraphQLError]) -> list[GraphQLError]:
         processed_errors: list[GraphQLError] = []
 
-        for error in result.errors:
+        for error in errors:
             if self.should_mask_error(error):
                 processed_errors.append(self.anonymise_error(error))
             else:
                 processed_errors.append(error)
 
-        result.errors = processed_errors
+        return processed_errors
 
     def on_operation(self) -> Iterator[None]:
         yield
 
+        pre_execution_errors = self.execution_context.pre_execution_errors or []
+        self.execution_context.pre_execution_errors = self._process_errors(
+            pre_execution_errors
+        )
+
         result = self.execution_context.result
 
-        if isinstance(result, ExecutionResult):
-            self._process_result(result)
-        elif result:
-            self._process_result(result.initial_result)
+        if result is not None and result.errors:
+            result.errors = self._process_errors(result.errors)
 
 
 __all__ = ["MaskErrors"]