Cloudflare Containers: Vulnerability Allowing Reading of Residual Data from Other Tenants via Reused Blocks

1. Overview Article Title: How Cloudflare addressed a cross-tenant data exposure vulnerability in Containers Publisher: Cloudflare Publication Date: 2026-09-24 Source: Cloudflare Related Sources: Accomplish: Escaping the Cloudflare Sandbox, BleepingComputer Related Malware, Threat Groups, CVEs, Products: Cloudflare Containers, Cloudflare Sandboxes, Workers Paid, Linux dm-thin Severity: High (A vulnerability that could break the cross-tenant confidentiality boundary. Targeting specific victims, modifying active disks, and causing denial of service were not confirmed, and Cloudflare has found no evidence of malicious exploitation.) Fix Details: Corrected the source title and distinguished authorized research on production infrastructure from malicious theft. Outlined the stages of successful information exposure, residual risks in existing allocations, and countermeasures taken by both Cloudflare and customers. 2. Quick Summary In Cloudflare Containers