Get a security review of an infrastructure change before it merges, not a generic OWASP checklist

Review the following infrastructure change for security issues before it merges. Focus only on what this specific change introduces or alters — do not produce a general security checklist unrelated to the diff.

THE CHANGE
Terraform diff adding an S3 bucket policy that grants `s3:GetObject` to `Principal: "*"` for a bucket storing generated PDF invoices

SYSTEM CONTEXT
Invoice generation pipeline; bucket holds customer-facing PDF invoices with names, addresses, and line-item pricing, no payment card data

WHO/WHAT CAN REACH THIS
Bucket is currently only linked from authenticated customer portal pages, but the new policy would make objects fetchable by anyone with the URL, authenticated or not

COMPLIANCE OR POLICY CONSTRAINTS THAT APPLY
This data falls under our internal PII handling policy; not sure if GDPR data-residency rules apply since some customers are in the EU

For every issue you find, state: what specifically in the change causes it, how it could actually be exploited given the exposure surface described (not a hypothetical worst case unrelated to this system), and how confident you are that it's a real issue versus something that needs a human to verify (e.g., you can't see the full IAM policy, only this diff). Rank issues by exploitability given the actual exposure surface, not by textbook severity alone — a critical-sounding misconfiguration on an internal-only service reachable by nobody outside a VPN is lower priority than a moderate one on something internet-facing. If the change looks fine, say so plainly rather than manufacturing a minor finding to seem thorough. Do not invent a specific CVE, compliance clause, or statistic — if you reference a class of vulnerability or a compliance requirement, describe it generically and tell me to verify the specific clause number or CVE ID myself rather than stating one as fact.

WHAT NOT TO DO
Do not produce a generic 'security best practices' list disconnected from this specific diff. Do not flag something as an issue without stating the concrete exploit path — 'this could be a security risk' without a mechanism is not a usable finding.

OUTPUT FORMAT
1. Verdict: change looks safe to merge / has issues that should block merge / has issues worth fixing but not blocking, with one-line reasoning.
2. Findings table: issue, exact location in the diff, concrete exploit path given the exposure surface, confidence (high/needs-human-verification), severity given actual exposure.
3. Anything you could not fully assess because you can't see surrounding context (e.g., the full network policy, the rest of the IAM role) — name exactly what additional context would let you finish the assessment.