diff --git a/sentry_sdk/client.py b/sentry_sdk/client.py
index e3c6370c9c..59f9018912 100644
--- a/sentry_sdk/client.py
+++ b/sentry_sdk/client.py
@@ -358,7 +358,8 @@ def _get_options(*args: "Optional[str]", **kwargs: "Any") -> "Dict[str, Any]":
         rv["event_scrubber"] = EventScrubber(
             send_default_pii=False
             if rv["send_default_pii"] is None
-            else rv["send_default_pii"]
+            else rv["send_default_pii"],
+            recursive=True,
         )
     elif has_data_collection_enabled(rv) and rv["event_scrubber"]:
         warnings.warn(
diff --git a/sentry_sdk/scrubber.py b/sentry_sdk/scrubber.py
index 6794491325..c21f080f96 100644
--- a/sentry_sdk/scrubber.py
+++ b/sentry_sdk/scrubber.py
@@ -1,3 +1,4 @@
+import copy
 from typing import TYPE_CHECKING, Dict, List, cast
 
 from sentry_sdk.utils import (
@@ -111,12 +112,17 @@ def scrub_dict(self, d: object) -> None:
         if not isinstance(d, dict):
             return
 
-        for k, v in d.items():
+        for k, v in list(d.items()):
             # The cast is needed because mypy is not smart enough to figure out that k must be a
             # string after the isinstance check.
             if isinstance(k, str) and k.lower() in self.denylist:
                 d[k] = AnnotatedValue.substituted_because_contains_sensitive_data()
             elif self.recursive:
+                # Nested containers are often the caller's objects. Copy before
+                # walking them so scrubbing the event does not change that data.
+                if isinstance(v, (dict, list)):
+                    v = copy.deepcopy(v)
+                    d[k] = v
                 self.scrub_dict(v)  # no-op unless v is a dict
                 self.scrub_list(v)  # no-op unless v is a list
 
@@ -164,8 +170,18 @@ def scrub_spans(self, event: "Event") -> None:
         with capture_internal_exceptions():
             if "spans" in event:
                 for span in cast(List[Dict[str, object]], event["spans"]):
-                    if "data" in span:
-                        self.scrub_dict(span["data"])
+                    data = span.get("data")
+                    if not isinstance(data, dict):
+                        continue
+                    # PyMongo stores a logical session id here. "session" is on the
+                    # denylist because of cookies, and this value is not a secret.
+                    op_ids = data.get("operation_ids")
+                    session = op_ids.get("session") if isinstance(op_ids, dict) else None
+                    self.scrub_dict(data)
+                    if session is not None:
+                        restored = data.get("operation_ids")
+                        if isinstance(restored, dict):
+                            restored["session"] = session
 
     def scrub_event(self, event: "Event") -> None:
         self.scrub_request(event)
diff --git a/tests/test_scrubber.py b/tests/test_scrubber.py
index 211d6336ac..5181e4b83f 100644
--- a/tests/test_scrubber.py
+++ b/tests/test_scrubber.py
@@ -3,7 +3,7 @@
 
 from sentry_sdk import capture_event, capture_exception, start_span, start_transaction
 from sentry_sdk.scrubber import EventScrubber
-from sentry_sdk.utils import event_from_exception
+from sentry_sdk.utils import AnnotatedValue, event_from_exception
 from tests.conftest import ApproxDict
 
 logger = logging.getLogger(__name__)
@@ -283,3 +283,41 @@ def test_recursive_scrubber_does_not_override_original(sentry_init, capture_even
     (frame,) = frames
     assert data["csrf"] == "secret"
     assert frame["vars"]["data"]["csrf"] == "[Filtered]"
+
+
+def test_default_scrubber_scrubs_nested_secret(sentry_init, capture_events):
+    sentry_init()
+    events = capture_events()
+
+    try:
+        1 / 0
+    except ZeroDivisionError:
+        ev, _hint = event_from_exception(sys.exc_info())
+        ev["extra"] = {"user": {"password": "secret", "name": "ada"}}
+        capture_event(ev)
+
+    (event,) = events
+    assert event["extra"]["user"]["password"] == "[Filtered]"
+    assert event["extra"]["user"]["name"] == "ada"
+
+
+def test_recursive_scrub_leaves_caller_dict_and_mongo_session():
+    user = {"password": "secret", "name": "ada"}
+    event = {
+        "extra": {"user": user},
+        "spans": [
+            {
+                "data": {
+                    "operation_ids": {"session": "abc", "operation": 1},
+                    "password": "secret",
+                }
+            }
+        ],
+    }
+    EventScrubber(recursive=True).scrub_event(event)
+    assert user["password"] == "secret"
+    assert isinstance(event["extra"]["user"]["password"], AnnotatedValue)
+    assert event["extra"]["user"]["name"] == "ada"
+    assert event["spans"][0]["data"]["operation_ids"]["session"] == "abc"
+    assert isinstance(event["spans"][0]["data"]["password"], AnnotatedValue)
+