Documenso's sign-field-with-token.ts, used by the live document-signing UI, allows a recipient with the ASSISTANT role to fetch and complete fields belonging to any later-or-equal-order, not-yet-signed recipient in the same envelope, with no restriction on field type. A newer V2 signing path (sign-envelope-field.ts) explicitly blocks assistants from completing SIGNATURE fields, and the project's own test suite comments confirm this guard is absent from the V1 path used here.
Attack Parameters
Impact Assessment
CVSS Vector v3.1