Security: session hardening
Refresh token rotation with theft detection (family_id)
- Added family_id column to auth.sessions (migration 20260507000000_session_family.sql) grouping all tokens issued from the same login into a family
- On refresh, the new session inherits the parent's family_id
- If a revoked token is replayed (indicates the token was stolen after rotation), the entire family is immediately invalidated and a warning is logged — forcing re-authentication on all devices
SameSite=Strict on refresh cookie
- Access cookie stays SameSite=Lax (needed for top-level navigation)
- Refresh cookie upgraded to SameSite=Strict — it is only ever used for explicit POST to /api/auth/refresh, never via cross-site navigation
Refresh token TTL: 30 days → 7 days
- With rotation, active sessions auto-renew and effectively never expire
- Inactive sessions expire after 7 days instead of 30, reducing the theft window
Edouard Vanbelle