Cloudflare Sneezed, and the Internet Caught a Fever.

Aastha Thakker
Nov 20
6 min read

That day, November 18 felt like the web was running on borrowed stability. It began like another routine internet hiccup, X refused to load, support dashboards froze, and gamers got stuck in timeout limbo. But within hours, the pattern snapped into focus: half the web was suddenly speaking the same cursed phrase “Unable to establish a secure connection.”

The culprit? Cloudflare’s backbone systems slipped into an unhealthy state after a burst of abnormal traffic collided with a routing-layer failure. And since Cloudflare quietly sits at the front door of countless services, that tiny crack turned into a global choke point.

In simple terms: Cloudflare Went Offline… And So Did Everyone’s Productivity.

What is cloudflare? & What it does?

Cloudflare is the giant sitting quietly at the edge of the internet, acting as both a security shield and a global traffic router for millions of services. It accelerates web traffic through its worldwide CDN, filters threats using its WAF and DDoS mitigation layers, manages DNS at lightning speed, and keeps encrypted connections stable through its edge gateways. In simple terms: your request often touches Cloudflare before it reaches the actual website. That’s why countless platforms lean on it, social apps like X, workflow tools like Canva, gaming networks such as Riot’s League of Legends and Valorant, developer platforms like GitLab, and even business ecosystems like Shopify and HubSpot, and our very own ChatGPT. So when Cloudflare’s internal routing or inspection layers break, the blast radius is immediate. One fault in its edge pipeline, and services around the world feel as if someone pulled their plug.

Cause of Outage

Not a cyberattack. Not hackers. Just a configuration file that got too big.

The real problem started inside their own Bot Management system — the part that uses machine learning to decide whether incoming traffic is from a human or a bot. This system relies on a regularly refreshed “feature file,” which is created every few minutes by running a query on a ClickHouse database. A change made to the database’s permissions altered how the query behaved, causing it to return duplicate rows. Because of this, the feature file suddenly doubled in size.

Once this oversized file reached edge machines, the routing software buckled first, and that failure spilled into the proxy layer. The routing software on each machine expects the feature file to stay within a fixed size. When it received a file twice as large as normal, it simply couldn’t handle it and started failing. That failure cascaded into the core proxy layer, the part responsible for processing every request flowing through Cloudflare.

After realizing this wasn’t an attack but an internal data issue, Cloudflare engineers halted the rollout of the broken file and pushed back a stable version. All of this stemmed from a small permission change meant to improve database security and reliability which unintentionally changed how ClickHouse returned data. Cloudflare has acknowledged the chain reaction this caused and is working on stronger safeguards so that a single configuration change can’t ripple through the entire network again.

ClickHouse DB
   │
   │  (duplicate rows due to permission change)
   ▼
Oversized Feature File
   │
   │  (auto-generated & pushed globally)
   ▼
Cloudflare Edge Machines
   │
   │  (routing layer can't parse extra size)
   ▼
Routing Failure
   │
   ▼
Proxy Layer Crash
   │
   ▼
Global Outage

Why This Outage Was Different

What stood out in this incident wasn’t how long it lasted, but the reality check it delivered: the internet relies on layers of centralization that most risk models never account for. Teams usually focus on the resilience of their own stack app uptime, database health, cloud zones, message pipelines. But very few map the silent dependency between their users and an external edge network they don’t operate.

This disruption revealed how deeply organizations lean on infrastructure that rarely enters technical discussions. Once Cloudflare’s gateway stumbled, anything behind it lost its route to the outside world. For many people, it felt as if entire services had gone dark. Engineers monitoring their platforms saw normal metrics, completely unaware that requests weren’t even reaching their environment, making internal dashboards look steady while the internet appeared to be shrinking from the user’s side.

Rethinking Resilience at the Network Edge: Lessons, Gaps, and the Road Ahead

What many still treat as “outside the application” is, in practice, woven directly into its availability. When a service cannot operate without a specific gateway, DNS resolver, or filtering layer, that dependency becomes part of the system’s backbone, whether it’s documented or not.

It also exposed how uneven current reliability strategies truly are. Organizations confidently architect multi-region cloud deployments, yet quietly centralize critical entry points under a single vendor. The result is a lopsided resiliency model where core infrastructure is redundant, but ingress and security filtering rest on single point of failure. The outage made that imbalance impossible to ignore.

And Cloudflare isn’t the only example. Recent years have shown how fragile this ecosystem really is:

October 2025: An AWS disruption took down countless platforms.
July 2024: A flawed CrowdStrike update froze systems worldwide hospitals, airlines, and corporate networks all felt the shockwave.

Another weakness highlighted is the lack of deliberate behavior for edge-layer failures. Most systems instinctively shut down when their traffic patterns appear unsafe, which is fair for environments dealing with fraud or financial abuse. But many services could preserve minimal capability even if only read-only access, when their defensive edge is unreachable. For sectors like transport, communication, or government portals, this difference determines whether citizens experience inconvenience or complete system paralysis.

Visibility gaps were just as revealing. Teams relying solely on internal alerts found themselves without meaningful signs of trouble because nothing inside their stack was malfunctioning. What they needed was a direct view into the health of the external edge, not just CPU charts and app logs that remained misleadingly calm.

The next steps for organizations won’t be straightforward. They may need to diversify edge providers, build fallback DNS mechanisms, or design controlled degraded modes that keep essential functions alive during external disruptions. These decisions demand careful architecture, but the risk of not addressing them is far more expensive.

Cloudflare’s Response and Steps Toward Stronger Resilience

Matthew Prince, Cloudflare’s CEO, described this incident as the company’s most significant disruption since 2019 and issued a direct apology to both customers and the wider internet community. Cloudflare has launched a full internal review to understand the breakdown and prevent a repeat scenario.

To reinforce its infrastructure, the company outlined several upcoming improvements:

Stricter Configuration Handling: Cloudflare is introducing tighter validation for database configuration files to ensure oversized or malformed files cannot cascade through the system.
More Targeted Kill Switches: The network will gain finer-grained kill switches for specific features, enabling teams to isolate faulty components quickly without halting the entire platform.
Deep Audit of Core Modules: Engineers are conducting an extensive examination of all proxy modules, mapping out possible failure modes and addressing any related weaknesses ahead of time.

Together, these updates align with established best practices in resilience engineering and signal Cloudflare’s intention to strengthen reliability across its global network.

What Actually Needs to Change

The takeaway isn’t that Cloudflare messed up. Any large-scale platform will occasionally stumble and they recovered quickly. The real issue is that the modern internet is structured so tightly around a handful of providers that a single malfunction can simultaneously break McDonald’s ordering systems, disrupt ChatGPT, and lock out critical infrastructure. That’s not a Cloudflare problem that’s an architecture problem.

1. Multi-Provider Should Be the Default, Not an Upgrade

Relying on one CDN or security provider is asking for trouble. Traffic should be split across multiple independent networks. Yes, it increases cost. But the price of being unreachable for hours revenue loss, trust damage, operational chaos, is far higher.

2. Smarter AI Guardrails for Config Generation

If AI is generating config files, the safety mechanisms around deployment need to be much stronger. AI can propose, but humans must enforce boundaries. Size limits, syntax checks, sandbox tests, and phased rollouts aren’t optional they’re survival tools.

3. Circuit Breakers Everywhere

One unstable service should never be able to drag the entire system down with it. Circuit breakers exist for a reason, use them. A failing feature should isolate itself, not take everything down with it.

┌─────────────────────────────────────────┐
│         Bot Mitigation Service          │
│                                         │
│  ┌─────────────────────────────────┐    │
│  │        Circuit Breaker          │    │
│  │                                 │    │
│  │  If error_rate > 5%:            │    │
│  │    - Stop sending traffic here  │    │
│  │    - Alert engineers            │    │
│  │    - Route around problem       │    │
│  │    - Prevent cascading failures │    │
│  └─────────────────────────────────┘    │
└─────────────────────────────────────────┘

4. Independence Must Be Real, Not Just “Multi-Cloud” Marketing

Running workloads across AWS and Azure doesn’t help if both environments share the same brittle assumptions. True independence means:

Separate code paths
Separate deployment pipelines
Separate operational teams
Separate failure modes

Without that, “multi-cloud” is just an expensive illusion.

The Part Nobody Likes to Admit

All this requires more money, for redundancy, engineering capacity, monitoring, and architectural complexity. Most companies won’t invest in it. They’ll stick to single providers because it’s inexpensive and convenient. And then they’ll express shock the next time a major outage takes half the internet down. Another large-scale failure is inevitable. Maybe next time it’s AWS. Maybe Google Cloud. The names will change, but the pattern won’t unless the architecture does.