Default `EventScrubber` uses `recursive=False`, so nested denylist keys are not scrubbed |

The issue is in sentry_sdk/scrubber.py where EventScrubber.init sets recursive=False by default. Review sentry_sdk/client.py to see how the scrubber is instantiated. Write a test that creates an event with a nested denylist key (like under 'extra') and verify it's not scrubbed with the default, then is scrubbed after setting recursive=True. Check if there are performance concerns with deep recursion and consider limiting to known containers.

Static review of public source at commit 85e7ce66fcca. No traffic was sent to any Sentry environment.

EventScrubber only walks nested dict/list values when recursive=True, and that flag defaults to False:

sentry_sdk/scrubber.py:

class EventScrubber:
    def __init__(
        self,
        denylist: "Optional[List[str]]" = None,
        recursive: bool = False,
        ...
    ) -> None:

if isinstance(k, str) and k.lower() in self.denylist:
    d[k] = AnnotatedValue.substituted_because_contains_sensitive_data()
elif self.recursive:
    self.scrub_dict(v)
    self.scrub_list(v)

The default client wires a scrubber without enabling recursion:

sentry_sdk/client.py:

rv["event_scrubber"] = EventScrubber(
    send_default_pii=False
    if rv["send_default_pii"] is None
    else rv["send_default_pii"]
)

Top-level keys such as authorization are scrubbed; the same key nested under extra, request.data, or breadcrumb data is not. Integrators who assume “Sentry scrubs secrets by default” get shallow coverage only.

Suggested change:

• Default recursive=True on EventScrubber, or pass recursive=True from the client bootstrap.
• If recursion cost is the concern, recurse only into known containers (extra, request.data, breadcrumb data, frame vars) rather than the whole event.
• Document the flag next to send_default_pii in the scrubbing guide.

Severity: low–medium data-protection hardening (secret leakage via nested event fields). No proof-of-concept; no events were submitted.

Happy to send a focused PR + regression test with a nested denylist key if useful.