GHSA-86fh-w43w-338c: Decidim: Verification admins can access supplied IDs from other organizations

Description The verification admin mutation flow allows accessing, verifying, and rejecting participants records from another tenant. Technical description The verification admin controllers loads pending_authorization_id with a raw Authorization.find(...) and then authorizes the record without checking whether it belongs to current_organization. Reproduction steps: 1. An org2 participant uploads their ID: <img width="2184" height="1288" alt="decidim-verification-01" src="https://github.com/user-attachments/assets/c6713454-c787-4795-b852-3c2c672358d6" /> 2. An admin from another organisation, in this case org1, is able to open the ID from org2 by opening request 35, e.g http://localhost:3001/admin/id_documents/pending_authorizations/35/confirmations/new <img width="1539" height="1037" alt="decidim-verification-02" src="https://github.com/user-attachments/assets/6ed646de-a501-4964-8467-013ada55ce2d" /> 3. The admin then approves this request by looking up the ID in the picture (not shown in this image, but a real ID would expose this) <img width="1542" height="652" alt="decidim-verification-03" src="https://github.com/user-attachments/assets/c7ee5bea-3fa2-43d9-8330-8d834f34a9af" /> 4. Now the request has been approved, which can be seen from the org2 participant authorizations page: <img width="2279" height="720" alt="decidim-verification-04" src="https://github.com/user-attachments/assets/55ee1bab-d396-4e0f-803f-21dc31a2c125" /> Impact A tenant admin can access, reject or approve another tenant's id_documents requests. Patches See https://github.com/decidim/decidim/pull/16666 Workarounds Disable the "Identity documents" verification Reference OWASP A01:2021 Broken Access Control Credits This issue was discovered in a security audit organized by the Decidim Association and made by Radically Open Security against Decidim financed by NGI.