Build a focused STRIDE threat model for a feature

Create a focused threat model for this feature:
Users upload CSV reports. A worker parses files from object storage and stores derived rows. Users download only reports owned by their organization.

Assets, actors and operating assumptions:
External authenticated users; organization data must remain isolated. Upload size is capped at 10 MB. Worker permissions and object-key checks are not yet documented.

List the assets, components, trust boundaries and data flows actually supported by the design. Mark inferred elements and unresolved assumptions.

Create a concise threat table using applicable STRIDE categories: spoofing, tampering, repudiation, information disclosure, denial of service, and elevation of privilege. For each threat, identify the affected component, realistic attacker action, prerequisite, concrete impact, existing control with a design reference, and proposed mitigation.

Prioritize the most consequential plausible scenarios; explain the basis without invented numeric probabilities. Distinguish documented controls from suggestions. Finish with verification tasks and the design questions that could change the assessment. This is a design review, not evidence of a completed security test.