diff --git a/karton/core/task.py b/karton/core/task.py
index 4d8c34b..251e931 100644
--- a/karton/core/task.py
+++ b/karton/core/task.py
@@ -408,7 +408,12 @@ def unserialize_resources(value: Any) -> Any:
         if parse_resources:
             task_data = json.loads(data, object_hook=unserialize_resources)
         else:
-            task_data = orjson.loads(data)
+            try:
+                task_data = orjson.loads(data)
+            except orjson.JSONDecodeError:
+                # Fallback, in case orjson raises exception during loading
+                # This may happen for large numbers (too large for float)
+                task_data = json.loads(data, object_hook=unserialize_resources)
 
         # Compatibility with Karton <5.2.0
         headers_persistent_fallback = task_data["payload_persistent"].get(
diff --git a/tests/test_core.py b/tests/test_core.py
index 831c534..9ebb811 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -55,3 +55,18 @@ def test_matching_filters(self):
         self.assertTrue(task.matches_filters([{"A": "a", "B": "b"}]))
         self.assertFalse(task.matches_filters([{"Z": "a"}]))
         self.assertFalse(task.matches_filters([{"A": "a", "Z": "a"}]))
+
+
+class TestTaskLargeNumber(unittest.TestCase):
+    def test_large_number(self):
+        # Case from https://github.com/CERT-Polska/karton/issues/224
+        huge_n = 16500472521988697010663112438705807640072764589479002554256260695717317064262484691290598356970646828426660349407212809681822203919126081272297252018228030950728477136113932493730960235450313211028445802933417736042246471737169968152424614291341808025585752848637795661794780420312612645575283548111399362423653839834760368929525863676430601132093478720051122016787902563729760403548823660511230280753799912283221065068155277355752466002679387284450151073598015621110653783630539129630982849849675891985711599794713831157549822527748863844615219682824485519877354977586980738215172053213147055330238573803265248619061
+        task = Task(
+            headers={},
+            payload={
+                "e": 65537,
+                "n": huge_n,
+            }
+        )
+        task = Task.unserialize(task.serialize(), parse_resources=False)
+        self.assertTrue(task.payload["n"] == huge_n)