// CloudflareMEDIUM
Cloudflare patched a vulnerability in its Containers and Sandboxes platforms that could allow one customer to recover residual disk data from another tenant on the same physical host. The flaw stemmed from the skip_block_zeroing option in dm-thin provisioning failing to clear physical blocks before recycling them for new workloads. Cloudflare found no evidence of malicious exploitation and remediated the issue by disabling the problematic setting, retiring existing container disks, and clearing image caches.
- Cybersecurity News Review - Week 40 (2026)(opens in a new tab)
- Cloudflare Fixes Cross-Tenant Data Exposure in Containers - Info(opens in a new tab)
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