CVE-2026-105851: Payload: Field access control bypass on auth collections

## Impact Payload's duplicate operation copies field values from the source document even when a field is hidden, or its `access.read` or `access.create` rule would reject the value for that caller. The `disableDuplicate` collection setting, enabled by default on auth collections, did not stop this. ## Patches Users should upgrade Payload packages to `>= 3.90.0` or `>= 4.0.0-canary.34`. ## Workarounds Add a beforeDuplicate field hook to fields and set the value to empty or your default value.