Cloudflare DMARC Management is now generally available

When we first launched DMARC Management, it was driven by a simple belief: every domain on the Internet deserves strong email authentication, and cost should never be the reason it doesn't happen. As part of our mission to help build a better Internet, we made DMARC Management available for free to every Cloudflare customer. We wanted to give everyone the tools to understand and improve their DMARC posture without needing to hire an email security consultant or parse XML report files by hand.

Today, we are taking that commitment further. Cloudflare DMARC Management is now generally available, with a redesigned experience built to help you reach full DMARC enforcement as easily as possible.

^{The DMARC Management dashboard offers a unified view of your email authentication posture.}

Every time someone receives an email "from" your domain, their email provider asks a simple question: did the real owner of this domain actually send this? Without a way to answer that question, anyone can send an email pretending to be you and your recipients will have no way to tell the difference.

Email authentication is the set of DNS records that answers that question. There Continue reading

Growing the Cloudflare AI team with talent from Ensemble AI

Today, we’re excited to share that key members of the team at Ensemble AI are joining Cloudflare to help accelerate our work in AI infrastructure and make it easier for developers to run powerful AI models efficiently at scale.

Ensemble AI, founded in 2023 in San Francisco, has spent the last few years focused on one of the most important challenges in AI: making large models faster, smaller, and more cost-effective to serve, without sacrificing quality. The team has developed new approaches to model compression and efficient inference that are designed to reduce the memory, compute, and deployment overhead of large language models and multimodal architectures.

As AI becomes a core part of how developers build applications, the economics of inference matter more than ever. Models are getting larger; workloads are becoming more dynamic. And customers increasingly expect AI to be available everywhere: globally distributed, fast, reliable, and affordable. Bringing the Ensemble AI team into Cloudflare strengthens our ability to make that possible.

The team at Ensemble AI has focused on preserving the structure inside modern AI models while reducing the cost of running them. Instead of treating model efficiency as only a quantization or hardware problem, Continue reading

Scaling Security Insights: how we achieved a 10x increase in global scanning capacity

Security Insights provides actionable security recommendations for every Cloudflare account. To find these insights, we perform regular scans for all accounts, zones, and DNS records, looking for potential security risks and misconfigurations.

However, two key issues emerged. First, our scans were too infrequent. Scans were only being performed every week or two, and therefore newly introduced security risks could remain undetected for up to two weeks. Second, automatic scanning was opt-in for many free plan accounts – meaning lots of accounts weren’t being scanned at all.

The risks of infrequent or nonexistent scans are rising: as automated attacks accelerate, the window for detecting security misconfigurations is shrinking. Making sure that we’re finding these issues for all of our customers is crucial to our aim of building a better Internet for everyone.

We calculated that to increase our scanning frequencies and enable automatic scanning for all accounts, we would need to increase our scanning throughput by around 10x on average – from 10 scans per second to 100 per second. But our system was already struggling with its load: millions of events were filling up our backlog waiting to be processed; our API was frequently timing out; our processes were crashing. Continue reading

Route public traffic to private applications with Cloudflare

For most of the Internet’s history, public and private infrastructure operated as separate worlds. Public applications lived behind content delivery networks (CDNs) and web application firewalls (WAFs). Private applications lived behind virtual private networks (VPNs), firewalls, and separate operational stacks. We think that distinction is becoming obsolete.

Many of the applications organizations care about are not public websites. They are internal APIs, AI agent backends, MCP servers, operational tools, and services that were never designed to be exposed to the public Internet. Yet these applications still need modern security, performance, and programmability services. Security should be a property of the traffic reaching an application, not an accident of where the application happens to sit.

Until now, applying those services to private applications often required public IPs, firewall exceptions, connector software, or complex networking. As a result, many private applications missed out on capabilities such as WAF, bot management, rate limiting, caching, traffic acceleration, rewrites, and Workers, despite needing the same protections and controls as public-facing applications.

Today, we're launching Application Services for Private Origins in closed beta for eligible Enterprise customers. Customers can now securely route traffic to private origins without exposing those origins to the public Internet. This allows Continue reading

Defend against frontier cyber models: Cloudflare’s architecture as customer zero

A few weeks ago, we wrote about Project Glasswing and what we observed when we pointed cyber frontier models at our own code. Since then, we’ve seen that the part of the post that has resonated most deeply is the argument that the architecture around the vulnerability matters more than the speed of the patch.

In the conversations we've had with CISOs and security teams since, the questions have been consistent: what does our architecture actually look like, what should we monitor for, where do we start, and how can Cloudflare help?

Before getting into the details: the architecture below is built almost entirely from Cloudflare's own products, because Cloudflare security is customer zero for the security products we build. The Cloudflare stack already exists in front of our code, employees, and customer-facing applications. If you're a Cloudflare customer, every layer below is available to you today. If you're not, the principles still apply to whatever stack you've built.

In the previous post, we showed how a cyber frontier model like Mythos changes the attacker’s timeline. It can find vulnerabilities, reason through exploit chains, and generate working proofs faster than earlier models. Continue reading

Turning Cloudflare’s threat indicators into real-time WAF rules

Cloudflare’s Threat Events provides security analysts with a window into the global threat landscape. The platform offers a peek into the immense traffic that Cloudflare processes every day, so you can see in real time which IPs are attacking specific industries or which threat actors are trending globally. However, translating that visibility into active mitigation has often been a manual, reactive process.

Security teams have faced a recurring frustration: knowing that certain IP addresses were associated with specific threat actors (like Tycoon 2FA or RaccoonO365) or had been seen targeting their specific industry in other regions, but they couldn't easily automate the blocking of these high-risk IPs within their own WAF unless they manually configured the rules. 

We are excited to announce a new integration that brings Cloudflare’s vast threat intelligence directly into your WAF engine: you can now write proactive rules using live intelligence data. This means you can add more intelligence context to protect your application against known bad actors — before they even attempt to touch your infrastructure.

By populating specialized fields during the early stages of a request, the WAF can now screen traffic based on:

• Who is attacking by matching specific threat actor Continue reading

Your AI bill is out of control. Cloudflare can fix it now. 

There isn't a CIO on the planet not worried about AI spend right now. CFOs are increasingly nervous, too.

For fear of falling behind, many companies have pushed their employees to use AI as aggressively as possible. The edict was clear: "Move fast, we'll figure out the bill later." And for the most part, it worked: AI has been genuinely transformational for the teams that leaned in.

But the costs are real: we’ve heard countless horror stories of huge bills and painful overages on token spend.

Today, we're announcing spend controls in Cloudflare AI Gateway, and a closed beta for identity-driven budgets and routing using Cloudflare Access and your existing identity provider.

As we’ve spoken with hundreds of companies about their AI strategy, we’ve seen a common story:  The company gives every engineer access to frontier models through a shared API key. Usage takes off. At the end of the month, finance pulls the invoice and nobody can explain where the money went. Was it the machine learning team training a new pipeline? Was it an intern running Claude Opus on email triage? Was it a runaway continuous integration job that burned through 50 million tokens in a weekend? Continue reading

VoidZero is joining Cloudflare

VoidZero, the company behind Vite, Vitest, Rolldown, Oxc, and Vite+, is joining Cloudflare. As part of this change, all team members of VoidZero are joining Cloudflare, too.

Before saying anything else, we want to make the most important thing clear: Vite, Vitest, Rolldown, Oxc, and Vite+ will stay open source, vendor-agnostic, and community-driven. Nothing about that changes.

Cloudflare's mission is to help build a better Internet. And a better Internet is an open Internet. Developers need choice, frameworks need a neutral foundation, and applications need to be portable. It is not reasonable to expect the entire web ecosystem to build around a single vendor. The most important tools and frameworks are portable by design.

Vite is one of the few foundational tools that the whole JavaScript ecosystem agrees on. It earned that position by being fast, excellent, portable, and vendor-neutral. One of the best ways Cloudflare can help build a better Internet is by investing in that foundational open source toolchain. A toolchain that makes the Internet better for everyone, not just people who use Cloudflare or choose to host with us.

Over the last few years we've invested heavily in making Cloudflare the best Continue reading

Enforcing the First AS in BGP AS_PATHs

Some recent route hijacks reported by Spamhaus captured our attention. In many of these hijack attempts, an apparent bad actor took advantage of unused autonomous system numbers, or ASNs. Notably in these hijacks, the actor appears to be creating fake AS_PATHs toward destinations, misdirecting traffic down an unexpected path. 

By creating forged AS_PATHs, the hijacker is attempting to lead traffic somewhere it isn’t normally meant to go while also trying to conceal their identity. A hijacker could strip enough information away from a network path that they could pretend to be the origin of a Border Gateway Protocol (BGP) prefix themselves. Attackers can use this hijacked route to intercept traffic and for other nefarious purposes.

There is a simple solution for these cases: basic verification that a BGP peer autonomous system (AS) always includes their network as the “First AS” in an advertised route. To get a sense of how well these safeguards are implemented, we stress-tested several major networks and researched their BGP implementations. Read on to see what we learned.

The idea that an actor is creating fake AS_PATHs is supported when we take a closer look at implausible AS Continue reading

How we reduced core unit boot time from hours to minutes

Cloudflare's core is the centralized data centers that run our control plane, billing, and analytics — distinct from the globally distributed edge that handles user traffic. Core servers are bare metal, and when issues happen during reboot, the consequences can cascade fast. 

Their boot sequence is orchestrated by UEFI, the modern firmware standard that initializes hardware and hands off control to the operating system. Small quirks in that handoff can have outsized consequences.

After a routine firmware update, some of our core servers were taking four hours to come back online, rather than just minutes as they did before. What should have been a one-day fleet-wide rollout was stretching into multi-day slogs. New nodes faced the full timeout gauntlet on their very first boot. Maintenance windows ballooned. Engineering teams had to babysit upgrades that should have run unattended. 

The behavior we saw was brought to light when we were bringing nodes online that had been powered off for an extended period. These nodes’ firmware was out of date and required multiple updates to resolve. Combine this with recent updates to the boot protocols used by servers in some of our locations, and boot times on the affected Continue reading

How we built Cloudflare’s data platform and an AI agent on top of it

Cloudflare processes more than a billion events every second. Our network spans 330+ cities in 120+ countries. Behind every HTTP request, every Worker invocation, every R2 read operation, there is data, and a lot of it.

For years, that data was not very easy to access. It lived in dozens of production databases, ClickHouse clusters, Kafka streams, Google Cloud buckets, BigQuery datasets, and a long tail of pipelines. To answer a simple question like "How many domains that signed up today are in the Top 100 by traffic?", an analyst at Cloudflare had to know which system to ask, what credentials to use, what query language to write, and whether the data they were looking at was sampled, fresh, or seven-days stale. As a result, it was difficult to glean informed insights from the data.

To solve this problem, we built two in-house tools: Town Lake, Cloudflare's unified data analytics platform, and Skipper, an AI data agent that runs on top of it. Town Lake is a single SQL interface to everything Cloudflare knows, and Skipper is how anyone at Cloudflare can ask questions in plain English and get correct, auditable answers back in seconds.

This is the story Continue reading

Iran’s Internet is partially restored, Cloudflare Radar data shows

On Tuesday, May 26, Iran’s vice president announced that Internet access had started to be restored in the country after being cut off almost three months ago, following the launch of U.S. and Israeli attacks on February 28.

Cloudflare Radar data confirms increased activity and indicates a partial restoration of the Internet in Iran. In this blog post, we’ll examine a range of data points that provide a lens into this prolonged shutdown – and the signs that Iran’s citizens are increasingly able to connect once again. As the situation continues to unfold, Radar will have the latest data on Iran’s connectivity.

Iranian citizens have experienced two national Internet shutdowns this year. The first began on January 8 around 16:30 UTC (20:00 local time), and we explored the impact seen over the first few days in a blog post. Traffic from Iran remained near zero until January 21, when a small amount of traffic returned, only to disappear a little over 24 hours later. A similar brief restoration also occurred on January 25, before traffic recovered more fully beginning on January 27.

In late February, as military strikes on Iran escalated, a second Continue reading

Announcing Claude Compliance API support with Cloudflare CASB

Today, we are extending Cloudflare’s cloud access security broker (CASB) to support the Claude Compliance API. Security and compliance teams can now monitor Claude usage directly in the Cloudflare dashboard. No endpoint agents required.

Enterprise security teams have long struggled to see how users interact with sanctioned and unsanctioned applications. The rapid adoption of AI applications has made this harder. Employees spend significant time in these new surface areas, and their interactions differ from traditional SaaS: users upload files, share freeform prompts, and providers generate content that may contain sensitive data.

Cloudflare CASB helps solve this problem. One API integration gives you out-of-band visibility and control over the applications your organization uses. This integration builds on our existing support for AI governance, extending coverage over the most common tools security teams now manage. 

AI adoption has outpaced security governance. While IT and security teams raced to enable AI tools for productivity, the controls lagged behind. Most organizations today operate with partial visibility: they may block unauthorized AI tools at the network layer, but they cannot see what happens inside sanctioned ones.

This matters because AI tools are not like traditional SaaS Continue reading

Announcing Claude Managed Agents on Cloudflare

Cloudflare and Anthropic have collaborated to integrate Claude Managed Agents with Cloudflare Sandboxes. Our new integration gives you more control over your agent sandboxes, secures connections to private services, and improves observability.

In the past year, Cloudflare’s Developer Platform has expanded to give more developers the tools they need to run agents at scale. This includes:

• Sandboxes for full stateful Linux microVMs at scale

• Agents SDK, providing simple and customizable agent framework

• Browser Run, which gives agents fully programmable and observable browsers

• Dynamic Workers, allowing for dynamic sandboxed code execution at massive scale

Our goal is to make Cloudflare the simplest, most secure, and most programmable cloud for agents.

Integrating with Claude Managed Agents is another step in this direction. You can run your agent loop on the Claude Platform, while using Cloudflare to execute code, secure connections, and run custom tool calls.

To get going in just minutes, we’ve created a default deployment template that gives you the following:

• Enhanced security - Run all agent traffic through customizable proxies. This allows you to securely inject credentials, prevent data exfiltration, and better observe how your agents interact with the outside world.

• Sandbox control and observability - Get Continue reading

Project Glasswing: what Mythos showed us

For the last few months, we've been testing a range of security-focused LLMs on our own infrastructure. These LLMs help identify potential vulnerabilities in our own systems, so we can fix them – and they also show us what attackers are going to be able to do with the latest models.

None of these LLMs has captured more attention than Mythos Preview, from Anthropic. A few weeks ago, we were invited to use Mythos Preview as part of Project Glasswing. We soon pointed it at more than fifty of our own repositories – to see what it would find, and to see how it works.

This post shares what we observed, what the models did well and what they didn't, and how the architecture and process around them needs to change, so they can be used at scale.

Mythos Preview is a real step forward, and it's worth saying that plainly before getting into anything else. We've been running models against our code for a while now, and the jump from what was possible with previous general-purpose frontier models to what Mythos Preview does today is not just a refinement of what came before.

It's Continue reading

Our billing pipeline was suddenly slow. The culprit was a hidden bottleneck in ClickHouse

At Cloudflare, we are heavy users of ClickHouse, an open-source analytical database management system. We redesigned one of our largest ClickHouse tables to add a column to the partitioning key. The change enabled per-tenant retention on a table that serves hundreds of internal teams. The design went through several rounds of revision and review with engineers across multiple teams before we landed on the final approach. But a few weeks after rollout, the jobs that produce most of Cloudflare's bills were running up against their hard daily deadline.

All the usual suspects looked clean: I/O, memory, rows scanned, parts read. Everything we would normally check when a ClickHouse query is slow appeared to be normal. The problem turned out to be lock contention in query planning, something we'd never had reason to look for before.

This is the story of how this migration exposed a hidden bottleneck in ClickHouse's internals, and the patches we wrote to fix it.

We use ClickHouse to store over a hundred petabytes of data across a few dozen clusters. To simplify onboarding for our many internal teams, we built a system called "Ready-Analytics" in early 2022.

The premise is Continue reading

Browser Run: now running on Cloudflare Containers, it’s faster and more scalable

We’ve enabled higher usage limits, faster performance, and better reliability for Browser Run by rebuilding on top of Cloudflare’s Containers.

You can now spin up 60 browsers per minute via the Workers binding and run up to 120 concurrently — 4x the previous limit. Also, Quick Action response times dropped more than 50%. You don't need to change anything: these improvements are live today. On top of that, we’re shipping fixes and new features faster than before. Read on to learn how we did it and see the data.

Browser Run enables developers to programmatically control and interact with headless browser instances running on Cloudflare’s global network. That’s useful for end-to-end testing of web applications, securely investigating suspicious URLs, and leveraging how browsers can easily render PDF documents, amongst other quick actions like capturing screenshots and extracting content. More recently, it’s become a critical enabler of AI agents to interact with the web. We’re building Browser Run to be the go-to platform to responsibly utilize automated browsers securely at massive scale.

Before adopting Cloudflare Containers, we shared infrastructure with Browser Isolation (BISO). While technically similar, BISO’s larger container images slowed Continue reading

When “idle” isn’t idle: how a Linux kernel optimization became a QUIC bug

CUBIC, standardized in RFC 9438, is the default congestion controller in Linux, and as a result governs how most TCP and QUIC connections on the public Internet probe for available bandwidth, back off when they detect loss, and recover afterward. At Cloudflare, our open-source implementation of QUIC, quiche, uses CUBIC as its default congestion controller, meaning this code is in the critical path for a significant share of the traffic we serve.

In this post, we’ll tell the story of a bug in which CUBIC's congestion window (cwnd) gets permanently pinned at its minimum and never recovers from a congestion collapse event.

The story starts with a Linux kernel change aimed at bringing CUBIC into line with the app-limited exclusion described in RFC 9438 §4.2-12 — a fix to a real problem in TCP that, when ported to our QUIC implementation, surfaced unexpected behaviors in quiche. It has a happy ending: an elegant (near-)one-line fix that broke the cycle.

Before we dive into the core problem, a quick refresher on Congestion Control Algorithms (CCAs) may help to set the stage.

The central knob a CCA turns is the congestion window (cwnd Continue reading

Building for the future

This afternoon, we sent the following email to our global team. One of our core values at Cloudflare is transparency, and we believe it's important that you hear this directly from us because it’s a major moment at Cloudflare. 

Team:

We are writing to let you know directly that we’ve made the decision to reduce Cloudflare’s workforce by more than 1,100 employees globally. 

The way we work at Cloudflare has fundamentally changed. We don’t just build and sell AI tools and platforms. We are our own most demanding customer. Cloudflare’s usage of AI has increased by more than 600% in the last three months alone. Employees across the company from engineering to HR to finance to marketing run thousands of AI agent sessions each day to get their work done. That means we have to be intentional in how we architect our company for the agentic AI era in order to supercharge the value we deliver to our customers and to honor our mission to help build a better Internet for everyone, everywhere. 

Today is a hard day. This decision unfortunately means saying goodbye to teammates who have contributed meaningfully to our mission and to building Cloudflare Continue reading

How Cloudflare responded to the “Copy Fail” Linux vulnerability

On April 29, 2026, a Linux kernel local privilege escalation vulnerability was publicly disclosed under the name "Copy Fail" (CVE-2026-31431). Cloudflare’s Security and Engineering teams began assessing the vulnerability as soon as it was disclosed. We reviewed the exploit technique, evaluated exposure across our infrastructure, and validated that our existing behavioral detections could identify the exploit pattern within minutes. 

There was no impact to the Cloudflare environment, no customer data was at risk, and no services were disrupted at any point. Read on to learn how our preparedness paid off. 

Cloudflare operates a global Linux server infrastructure at an immense scale, with datacenters located across 330 cities. We maintain a custom Linux kernel build based on the community's Long-Term Support (LTS) versions to manage updates effectively at this volume. At any given time, we may utilize multiple LTS versions from various series, such as 6.12 or 6.18, which benefit from extended update periods.

The community regularly merges and releases security and stability updates which trigger an automated job to generate a new internal kernel build approximately every week. These builds undergo testing in our staging data centers to Continue reading