The check runs on every protected request, and it is a diff, not a lookup. The session presents the three version numbers it was issued with; policy reads the current server-side values and compares [3]. A consent version mismatch does not touch the session, it forces fresh authorization for the scope being requested; an account epoch or credential version mismatch invalidates the whole session family [4]. Three comparisons, two failure classes [19]. A single boolean has one, which is the whole argument.
Ordering does the rest. In the state machine the post describes, `reset_requested` carries no authority: it may open a short-lived verification challenge and send a message over a side channel, and it must not change the password, withdraw consent, reveal whether the account exists, or invalidate sessions [7]. Only `password_changed` advances the credential version and revokes established sessions [6]. The committed sequence is consume the token, update the credential, advance the credential version, revoke the relevant sessions, require a new authentication ceremony [17]. The post also declines to log the user in automatically afterwards, following OWASP's reasoning that auto-login adds complexity to authentication and session handling [10].
The asymmetry is what makes the coupled version expensive. Under coupling, one unauthenticated POST buys one revocation, and the victim pays for it with a full authentication ceremony [20]. The post grants that rate limits help, and then puts the correctness property somewhere a config value cannot break it: the authorization model has to stay right even when the limit is misconfigured, so revocation waits for proof of token possession and a committed password change [9]. That is the good bit of engineering here. Throttles are still needed, but per-account throttles alone can be used to lock out one customer and per-network throttles alone punish shared networks, so the recommendation is layered signals, a generic outward response, and alerting on repeated requests across many accounts or repeated token failures against one account [14].
Splitting the controls also splits the audit trail. A completed reset records the credential-version change and the session-family revocation as two events even though one transaction caused both [12], and the record carries policy name, subject, session family, old and new version numbers, consent purpose, reason code, correlation ID and timestamp, with the reset token and the new password never written [11].
What is on offer is one practitioner's default for a fintech forgot-password flow that has to survive audit, with revocation placed after the password is actually reset [13]. Nothing in it is measured. The claim that one policy boundary tests more easily than scattered `if (consent)` checks is asserted from experience, not from a defect count or a test-suite figure [16], and the author says outright that he doubts any fixed bot threshold transfers between a consumer wallet and a treasury dashboard, because traffic distribution, customer impact and support capacity set that number locally [15]. For the version scheme to transfer, you need session-family identifiers you can already revoke, server-side counters you can read on the hot path, and a client that can handle a re-consent response for one scope mid-session [4].
The verification is one request. Submit a reset for an account whose session you are holding, then call a protected endpoint with that session. If the second call fails before any token has been consumed, the reset form is a logout endpoint [7].
