CVE-2026-25574: payload-preferences has Cross-Collection IDOR in Access Control (Multi-Auth Environments)

A cross-collection Insecure Direct Object Reference (IDOR) vulnerability exists in the payload-preferences internal collection. In multi-auth collection environments using Postgres or SQLite with default serial/auto-increment IDs, authenticated users from one auth collection can read and delete preferences belonging to users in different auth collections when their numeric IDs collide.

Users are affected if ALL of these are true:

• Multiple auth collections configured (e.g., admins + customers)
• Postgres or SQLite database adapter with serial/auto-increment IDs
• Users in different auth collections with the same numeric ID

Not affected:

• @payloadcms/db-mongodb adapter
• Single auth collection environments
• Postgres/SQLite with idType: 'uuid'