Database permissions change doubles a bot-management feature file and crashes edge proxies (Cloudflare, 2025)
A ClickHouse access-control change made table permissions explicit, so a query without a database filter returned duplicate rows and doubled the size of the Bot Management feature file.
What happened
- The oversized file exceeded the module's hard limit of 200 features and triggered a panic in the Rust proxy code, producing widespread 5xx errors.Cloudflare outage on November 18, 2025
The failure pattern
Watch the pattern: Global change without a staged rollout
Safeguards that address it
CollectSEA's engineering analysis of what would have prevented or contained this failure.
- Validate generated configuration before global propagationCheck size, duplicates and schema of auto-generated files, and roll out gradually with a kill switch.
- Fail safe with last-known-good configurationConsumers should reject an invalid file and keep serving with the previous good version instead of panicking.
Related standards
CollectSEA's mapping through this incident's failure pattern; not an official determination by the standards bodies.
Building something similar?
Describe your design and see every precedent that applies, with safeguards you can hand to your coding agent.
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