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The Cloudflare Nov. 18 outage was caused by an internal database permission change that led to an oversized Bot Management file, which propagated globally and caused widespread 5xx errors across Cloudflare’s edge network.
Every IT leader has lived through the same moment: you’re going about your morning, maybe scanning dashboards or jumping into a meeting, when the steady hum of “everything’s fine” suddenly shifts. Users start pinging you. Systems that never blink start throwing errors. And for a split second, you wonder if it’s your environment or the world at large.
That’s what November 18, 2025, felt like for many. Just after 11:20 UTC, the internet didn’t break, but it definitely hit pause.
Websites that normally load instantly froze and login screens timed out. Major platforms like X and OpenAI sputtered with 5xx errors. And almost immediately, the chatter across engineering channels, NOC war rooms, and ops teams lit up with the same question: “Is this us… or is this Cloudflare?”
This time, it was Cloudflare.
Cloudflare explained later that a routine internal database permission change inadvertently caused one of their Bot Management “feature files” to balloon in size. This file is used constantly across their edge for traffic classification. It’s not glamorous, but it’s important, sort of the quiet piece of plumbing that everything relies on.
When it doubled in size, the software that consumes it began failing. Not everywhere at once, but close enough that the effect felt instantaneous. And that’s when the ripple turned into a wave (see our Bluewave pun!).
As Cloudflare describes it, within minutes:
From our vantage point at Bluewave, the pattern was familiar: when a core dependency fails in a distributed system, it rarely fails quietly. It fails loudly and in ways that look unrelated until the root cause surfaces.
This wasn’t a cyberattack, Cloudflare made that clear in their statement, it wasn’t a BGP leak, and it wasn’t one of those high-profile routing anomalies that make every global ISP sprint to their consoles.
It was simply an internal component failing everywhere at the same time. Sometimes that’s all it takes.
On paper, this outage lasted a few hours but it felt longer because it hit systems that sit in the direct path of everyday end-user life.
When Cloudflare stumbles, everything downstream feels it:
If you were operating a customer-facing service that morning, you felt it. Even for organizations not using Cloudflare directly, there’s a decent chance one of your critical third-party vendors does.
That’s the part we always remind clients: Your dependencies have dependencies. And when one of those upstream providers has a bad day, you inherit part of it, whether you realize it or not. This also holds true in the world of cybersecurity.
By 14:30 UTC, Cloudflare had core services back up and running. Full resolution came later in the afternoon. Their engineering teams moved quickly, communicated clearly, and published a transparent explanation, which is something we always appreciate in a vendor.
Looking at the root cause, what stands out isn’t how “big” the failure was, but how normal it was.
We see this pattern repeatedly in large-scale architectures where the butterfly effect is real and sometimes the butterfly is just a config file.
IT leaders tend to look for dramatic failures. But it’s the simple ones that tend to bite hardest, because they slip through guardrails we take for granted. It’s a good reminder that resilience isn’t about eliminating failure. It’s about designing systems that fail in smaller, more predictable ways.
Cloudflare’s long-term fixes are exactly what we’d expect from a provider at their scale:
All of these updates align with what we advise clients about building predictable, fault-tolerant environments.
We spend a lot of time at Bluewave helping organizations understand the systems behind the systems, including the dependencies, the latent risks, the operational blind spots. This outage reinforced three truths we talk about often:
Your customers judge you by how fast you recover, not how perfect your systems are. Cloudflare’s outage wasn’t catastrophic but is a reminder of how interconnected systems are.
As businesses become more distributed and more dependent on SaaS, cloud, and edge providers, these kinds of outages will continue to happen. The question isn’t whether a system you rely on will have another bad day, because it will. The question is whether your organization will be ready when it does.
This is why Bluewave’s Assess – Advise – Advocate Blueprint is so powerful for clients.
We help clients understand their dependencies, conduct Technology Assessments, prioritize, and build architectures that can absorb a hit without taking the business down with it.
Because resilience isn’t built in the middle of an outage, it’s built long before.
Want to assess your organization’s resilience? Talk to Bluewave.
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