stistigmem-node: quarantine review surface exposes and mutates other tenants' quarantined facts (cross-tenant BOLA)

Summary

On a multi-tenant stigmem node, a tenant administrator could list, read, and admit or reject quarantined facts belonging to other tenants. The list/count queries and _get_quarantined_fact in routes/quarantine.py lacked an f.tenant_id = identity.tenant_id predicate, and the garden lookup was not tenant-scoped — reached via the /v1/quarantine list and admit/reject endpoints.

Impact

Cross-tenant confidentiality (reading another tenant's quarantined content) and cross-tenant integrity (moderating — admitting or rejecting — another tenant's facts), gated only by a plain tenant write capability rather than a node-level admin authority.

Affected configurations

This is a cross-tenant break. It is exploitable only on deployments running the opt-in stigmem-plugin-multi-tenant (multiple tenants on one node). A default single-tenant node has only tenant="default" — there is no second tenant to cross — so it is not exploitable on default deployments. The rating is HIGH for the multi-tenant deployments the plugin exists to isolate.

Patches

Fixed in 0.9.0a12 (PR #728): AND f.tenant_id = identity.tenant_id was added to the list/count queries and _get_quarantined_fact; the garden lookup is now tenant-scoped; and any genuinely cross-tenant moderation is gated behind can_admin_federation() (node superadmin), not a tenant write capability. A tenant-B admin can no longer list, admit, or reject tenant-A's quarantined facts.

Workarounds

None other than upgrading to 0.9.0a12. Single-tenant deployments are unaffected.