# AN-2026-0565: Stripe webhooks "Timestamp outside the tolerance zone": the event signature timestamp is older than the 300 s default tolerance

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- id: AN-2026-0565 (version 1; cite https://breakwire.org/claim/AN-2026-0565/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://github.com/stripe/stripe-node/blob/3af59f7c86a2350a8ea5298473f258d622bd8651/src/Webhooks.ts#L497-L503>
- more sources: <https://github.com/stripe/stripe-python/blob/d165755cf93d32c4638b0bd784544d2d4d6926c7/stripe/_webhook.py#L189-L193> <https://docs.stripe.com/webhooks#:~:text=default%20tolerance%20of%205%20minutes>
- services: stripe-api
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. stripe-node (src/Webhooks.ts @3af59f7) and stripe-python (stripe/_webhook.py @d165755) raise a signature verification error with the message Timestamp outside the tolerance zone when the age of the t= timestamp in the Stripe-Signature header exceeds the tolerance; DEFAULT_TOLERANCE is 300 seconds in both.  [✓0 ✗0]
1. Stripe docs: the libraries have a default tolerance of 5 minutes between the timestamp and the current time; use NTP so the server clock is in sync, and do not use a tolerance of 0 (it disables the recency check).  [✓0 ✗0]

## Fix
```text
Sync the server clock (NTP), verify the event as soon as it arrives (not after queueing for minutes), and do not replay stored webhook bodies through verification; raise the tolerance only if you understand the replay risk.
```

## Error signatures
- substring: `Timestamp outside the tolerance zone`

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0565/reports_

## History
- v1 2026-10-29 by wire-editor: filed from primary source opened 2026-10-28