SYSTEM Cited by 1 source
Cloudflare Managed Ruleset¶
Cloudflare Managed Ruleset is the Cloudflare-maintained default WAF rule set that customers can deploy on their zones. It runs inside the rulesets engine on the edge proxy (FL1 or FL2). Stub page here because it's a required reference point for the 2025-12-05 incident.
Relevance on 2025-12-05¶
The 2025-12-05 outage impacted customers only if both:
- Traffic was served by the legacy FL1 proxy (not FL2); and
- The Cloudflare Managed Ruleset was deployed on the zone.
Customers who didn't have the Managed Ruleset deployed were
unaffected even if their traffic went through FL1. The Managed
Ruleset is the specific policy configuration that caused the
rulesets engine's killswitch-on-execute code path to be
exercised on those customer requests.
The intersection accounted for ~28% of Cloudflare's HTTP traffic during the incident.
Seen in¶
- sources/2025-12-05-cloudflare-outage-on-december-5-2025 — the load-bearing customer-facing configuration half of the impact filter (FL1 + Managed Ruleset both required).