Cloudflare fixes Containers cross-tenant flaw exposing customer data

The root cause of this vulnerability was a misconfigured shared storage pool that reused data blocks without clearing (zeroing) them between tenant allocations — a classic configuration management failure in multi-tenant environments. This meant one customer's container could read residual data left behind by another customer, including sensitive artifacts like directory listings, databases, and credentials. In cloud and shared infrastructure environments, proper memory and storage sanitization between tenant workloads is a fundamental security requirement, not an optional hardening step. While Cloudflare confirmed no actual data exposure occurred, the potential blast radius — credential theft, lateral movement, and data breaches across customer boundaries — underscores how infrastructure-level misconfigurations can completely undermine tenant isolation guarantees. This incident is a reminder that multi-tenant security is only as strong as the least-sanitized shared resource.