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Sessions_inactivity_timeout Not Enforced At Refresh_token Grant

The `sessions_inactivity_timeout` configuration is accepted and persisted by the Supabase Auth management API, but the refresh token grant does not check the session's last activity time, allowing stale refresh tokens to be redeemed indefinitely past the configured inactivity threshold.

highConfidence 82%GoTrue

Origin Analysis

The refresh token grant handler in GoTrue only validates the session's overall timebox and revocation status, but omits the synchronous check against `sessions_inactivity_timeout`; this is a design gap where inactivity enforcement relies solely on an asynchronous reaper instead of being enforced at the token exchange point.

1. Set `sessions_inactivity_timeout` to e.g. 60 seconds via `PATCH /v1/projects/{ref}/config/auth`. 2. Verify the value is persisted via `GET /v1/projects/{ref}/config/auth`. 3. Authenticate a user to obtain a refresh token. 4. Wait longer than the configured timeout without any session activity. 5. Exchange the stale refresh token at `POST /auth/v1/token?grant_type=refresh_token`. 6. Observe HTTP 200 and new tokens are issued, indicating the timeout was not enforced.

Fixing Code Block

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0x13 37 00 4F 9A 2D E1 700x08 B4 5C 22 71 D0 4A 16
0x48 8D 3D 22 01 00 00 E80x91 FF 0A 63 2E 57 B8 04
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0xFF 15 40 20 60 00 48 890xC3 90 7A 01 4C 28 B1 56
0x0F 1F 44 00 00 55 48 890xE5 C3 18 6D 92 0B 33 A7

Edge Case Audit

This change may cause unexpected logouts if the LastActiveAt/UpdatedAt timestamp is not comprehensively updated on all user activity, especially for long-lived access token usage. Concurrent refresh requests could race and both pass if the timestamp is not updated atomically within the same transaction. Enforcing this synchronously after a config change may immediately invalidate all existing sessions whose timestamps are older than the new threshold. Rollback strategy: set `sessions_inactivity_timeout` to 0 or disable the check via a feature flag. Before enabling, ensure every authenticated request updates the session's activity timestamp to avoid false positives.