Over the last month, the number of Large Language Model (LLM) penetration testing and orchestration frameworks has exploded. Just a few weeks ago, ARTEX — an open source agentic penetration testing system that automates offensive security workflows — was the only framework available. In just the last three days, we have seen over 50 framework families attempt to scan Cloudflare customers globally. The number of Internet Protocol (IP) addresses seen running these frameworks has grown into the thousands and continues to increase daily. The proliferation of these frameworks has significantly changed the status quo in cyber defense: defenders are struggling to keep up with the volumetric nature of these autonomously guided attacks.
ARTEX was taken down by its creator Autumn-27 on October 8. (“The malicious exploitation of this tool runs entirely counter to its original intent,” they wrote in Chinese.) But in the month since, the ecosystem has exploded with new fragmented versions of it. There are now over 12,000 repositories, with several hundred unique forks containing lineage from the original repository. Additionally, hundreds of other similar agentic orchestration frameworks have been created since October 8. Daily requests of AI penetration testing (pentesting) and exploitation tools has grown by 30x since October 1. Continue reading
The highest priorities for the transition to post-quantum cryptography are the basic building blocks of authenticated key-agreement protocols such as TLS. Without these building blocks in place, secure communication on the Internet will not be possible once cryptographically relevant quantum computers come online. However, today we rely on quantum-vulnerable cryptography for much more than TLS.
Privacy Pass is a protocol used by site operators like Cloudflare to help protect applications from abuse. One way we do this is by rate limiting individual clients so that no one client consumes too many of the site's resources. Normally this involves some combination of friction or loss of privacy for users: CAPTCHAs or other challenges to moderate traffic, along with accounts and fingerprinting to identify traffic.Privacy Pass was designed to avoid this tradeoff between friction and privacy. The basic idea is that a client gets issued a number of tokens, which they can redeem in exchange for access to the site. Crucially, each token is unlinkable to the client it was issued to, ensuring the client can use the site as they always had without sacrificing privacy.
With 10 years of deployment experience under our belts — using Privacy Pass for applications Continue reading
AI Agents now act on the web for millions of people. To a Site, an Agent can take many forms. It may be indistinguishable from a human user carrying out a task, or it might look like one visitor carrying many Users. This removes the ability for the Site to recognize, serve, and hold accountable the user or users behind the Agent, and causes the Site to face the costs when something goes wrong. This post argues that in order for Sites to maximize the access they provide to Agents, the ecosystem must develop new mechanisms to preserve the relationship between Sites and Users. Traditionally, in Security and Fraud Prevention, that requires three things: Identity, Reputation, and Accountability, allowing Sites to answer: Is the person acting being truthful about who they are? Is that person trustworthy? And who answers for the action?
“Personal AI Agents” (“Agents” for short) are automations that take instructions from a human (“User”) and pursue a goal by controlling a cloud computer or browser. They are usually hosted and maintained by an “Operator” as part of a managed service or consumer offering. Examples include Muse from Meta and dots from OpenAI, and more are launching all Continue reading
Personal agents are the intermediary between humans and the Internet, turning a person’s instructions into requests and actions on websites. A customer might ask a personal agent to compare products across your site, find support articles, or complete a purchase. To a site owner, all three interactions show up as automated traffic — and without a clear view of which agents are visiting and what they are doing, it can be difficult to know whether that traffic is helping your business or creating risk. Blocking agents altogether can feel like the safest choice, but it can mean losing customers. Better visibility into agent activity allows you to decide what access makes sense for your site.
Today, we’re launching new analytics to help you understand how personal agents access your site on behalf of humans, along with more granular access policies to put those decisions into practice. Together, they let you welcome agents on your own terms, and in ways that support your business.
Knowing which agent is behind a request turns unexplained automated traffic into traffic you can act on with confidence. Cloudflare maintains the largest verified bot directory in the world, and we are Continue reading
You run security at your organization. It’s 7:00 am, and you’re having breakfast. You receive a ping: a new critical vulnerability has been disclosed. Your team scrambles to compare vendor advisories, read technical research, check which systems run the affected software, and answer familiar questions from the business: are we affected, and what are we doing about it? Another disclosure arrives before that work is finished.
AI is changing both the volume and speed of critical vulnerability discovery. It can analyze large codebases at scale and surface deeply nested flaws that may have existed for years without being found through human review. That discovery momentum will put more pressure on security teams to understand the impact of each disclosure on their infrastructure.
To help security teams prepare, today we’re introducing Zero Wire: a public vulnerability intelligence feed on Cloudflare Radar, bringing the clarity of a news wire service to critical security developments. It helps security leaders and practitioners understand significant vulnerabilities and decide what to do next.
Zero Wire lives inside Cloudflare Radar under the security section.
Each briefing brings together a plain-language explanation of the vulnerability, who should investigate it, recommended actions, and links to Continue reading
On October 19, 2026, we learned about eMudhra’s eight shockingly weak keys: where eMudhra was trusted to pick a 115-digit number for their virtual combination lock protecting the Internet, they picked the number 4. Not even four digits, just the number 4. The other seven keys were similarly weak: 56, 66, 115, 155, 156, 230 and 237.
The next day, we wrote a blog post on the immediate action we took to mitigate this leak, and what customers needed to do on their end to stay secure. Now, we are sharing a more in-depth follow up on the evidence we’ve seen of exploitation, and the progress seen on visitors patching their systems.
Let's start with the scale of the problem. A certificate authority (CA) with weak keys this serious is unprecedented, and the potential consequences are significant. While there have been plenty of compromised certification authorities in the past (such as DigiNotar, TÜRKTRUST, and TrustWave), access to their keys has always been contained to a degree; these incidents gave a limited set of attackers or organizations the ability to issue fraudulent certificates. The eMudhra incident is fundamentally different; the affected intermediate private keys could be recovered almost Continue reading
Welcome to the 26th edition of Cloudflare's DDoS Threat Report. This edition covers the third quarter of 2026 — July, August, and September — and returns the series to its quarterly cadence following the combined H1 2026 volume. The analysis is produced by Cloudforce One, Cloudflare's Threat Intelligence organization, providing a comprehensive analysis of the evolving threat landscape of Distributed Denial of Service (DDoS) attacks based on data from the Cloudflare network.
Last week was one for the Internet security history books. First, eight eMudhra intermediate certificates were compromised, creating the possibility of forged certificates that could be used to impersonate servers. Then came php2shell: serious vulnerabilities in PHP, the runtime behind a large portion of the Web.
Cloudflare worked around the clock as these events unfolded to protect our customers and help protect the Internet. We shipped client updates and multiple mitigations, updated our web application firewall (WAF) with new rules to block attackers from exploiting the PHP vulnerabilities, and introduced a new feature called full transaction detection.
As always in situations like this, these new capabilities were made available on all plans, including Free.
Protecting systems from vulnerabilities like these is always an ongoing process, not a one-time event. The widespread adoption of AI allows attackers to discover new vectors with unprecedented speed and efficiency, so collecting real-world data to test our assumptions and strengthen defenses is essential.
That’s why today we're launching the Cloudflare PHP Capture the Flag challenge, run through our Bug Bounty program. We've put a deliberately vulnerable PHP installation behind our WAF, and we're inviting security researchers Continue reading
On September 8, 2026, we were alerted by a security researcher, Gadi Evron from Knostic, to a tenant isolation issue affecting the GLM-5.3 Workers AI model (@cf/zai-org/glm-5.3) starting on August 27, 2026. We have remediated the issue, and we restored the model on September 9. We have confirmed that no other model hosted on Workers AI was affected.
Between August 27 and September 9, a small number of customers using the GLM 5.3 Workers AI model received responses that contained data from other customers' requests made to the same model shortly before theirs. In total, 155 responses were affected, all to prompts longer than 681,280 tokens.
After excluding our own testing and the researcher's, the requests we identified are consistent in timing and volume with ordinary long-context use, not with someone repeatedly exploiting the bug. We found no evidence of deliberate exploitation.
Today we are publishing this report alongside a post from SGLang, the open-source inference engine that we use, as a coordinated disclosure. This post describes the bug that caused this issue, our response timeline, and the subsequent hardening we have conducted on our production SGLang deployments. We also detail our continued efforts with Continue reading
For ten days, auditors appointed by the Korea Internet & Security Agency (KISA) sat together with us and worked through 80 controls. That is what it took for a company headquartered in the United States, operating a global network serving Korean users, to be certified in South Korea. Cloudflare has now obtained South Korea's Information Security Management System (ISMS) certification under the ISMS-P framework.
For customers in Korea, this is more than a compliance checkbox. It is evidence that Cloudflare's security and privacy program has been examined not only for whether our controls exist, but for how they operate in the context of Korean law, the Korean language, and the particular expectations of Korean regulators.
The most visible result of this work is the Cloudflare account sign-up page. In most parts of the world, the line that sits above the sign-up button reads: "By continuing, I agree to Cloudflare's terms, privacy policy, and cookie policy."
A user signing up from South Korea sees something different. The Korean experience is triggered by the country selected at sign-up and by IP geolocation from within South Korea, and it breaks the same Continue reading
Today, we are expanding our web application firewall (WAF) by adding two new capabilities: full transaction detections and response rules. Full transaction detections evaluate each HTTP request alongside its response to identify evidence of exploitation. It helps answer both "Does this request look malicious?" and "What happened when the application handled it?" Response rules can then block the origin’s response before it reaches the requester.
These are valuable protections because the latest frontier models are uncovering vulnerabilities buried deep in widely used software, giving defenders clarity on what to fix — and attackers new paths to exploit. The recent php2shell vulnerability shows the stakes: a flaw in a common software component can put applications across the Internet at risk. AI agents scanning for vulnerabilities can be extremely persistent, adapting payloads using feedback, and chaining vulnerabilities, credentials, and permissions. An application's response can reveal whether an attempt worked and give an attacker information that helps them go deeper.
Inspecting incoming requests remains essential for stopping recognizable attacks before they reach an application. But some threats become clear only when the request is considered alongside what the origin returns. A suspicious input followed by a response exposing sensitive information tells Continue reading
Today, Calif.io, Wiz, OpenAI and Quarkslab disclosed two vulnerabilities in PHP, tracked as CVE-2026-109618 and CVE-2026-109619 and known as php2shell. The vulnerabilities affect all web servers running PHP 5.4 or later and they may allow an attacker to cause denial of service, remote code execution, and data exposure when an application processes specially crafted HTTP traffic.
Cloudflare has been part of a coordinated effort to deploy mitigations to protect the Internet, working with PHP foundation, OpenAI and Wiz among others. Cloudflare has developed and deployed web application firewall (WAF) protections since early October 2026, which were deployed about 9 hours ahead of public disclosure. Starting on October 21 3:02 am UTC, Cloudflare customers using our free or paid WAF were protected by default against php2shell.
Cloudflare successfully deployed multiple mitigations for all its customers while the vulnerability was leaked before the official release date and we observed attack traffic targeting our customers. We observed how attackers were mutating the attack payload to try to bypass our protections by tracking the volume of matches and cross-referencing with the rule logic.
Protecting against php2shell required more than standard request-based rules. Request data alone does not always provide enough evidence to distinguish an Continue reading
On October 19, 2026, at approximately 17:00 UTC, Cloudflare became aware that private keys associated with eight eMudhra intermediate certificates were compromised. These certificates were widely trusted by browsers, operating systems, and also within Cloudflare. Because the keys themselves are weak, an attacker can create a forged certificate for any domain and use it to impersonate servers to intercept or modify traffic. This is a serious security incident with implications across the Internet. For reference, here is a link to more information about how SSL certificates work and why they are so critical to the operation of the Internet.
We immediately prioritized patching critical services across Cloudflare to protect our customers ahead of the public disclosure of the vulnerability. Our security review has not identified active exploitation of this issue on Cloudflare services.
We have released updates for the Cloudflare One Clients, also known as WARP or the 1.1.1.1 app, and Cloudflare Tunnel, also known as cloudflared. We have also deployed mitigations across our CDN, Developer, and Zero Trust products. If you are using Cloudflare Zero Trust with Gateway and an up-to-date client (see below), you are automatically protected.
We prioritized updating services that use public certificates Continue reading
The recent disclosure of a major vulnerability in Citrix NetScaler pointed to a widespread weak point: a login page is an attack surface that can be used to compromise and access an application server. Indeed, the disclosures included an actively exploited flaw that allowed attackers to execute commands on affected gateways without signing in. As with any emergency patch, admins had to weigh cutting off or disrupting their users’ access with the risk of delaying a critical security update.
If you’re a NetScaler customer and you haven’t patched your instance, stop reading and go do that. This was a bad one. Once you’ve finished the patch, we’ll explore how to avoid a future fire drill by laying additional security controls.
This issue extends beyond NetScaler and can be applied to any internal application available on the Internet. Remote desktop portals, administrative consoles, and other publicly accessible authentication pages all deserve the same scrutiny: Does the intended audience require unrestricted Internet reachability? And can an attacker bypass this authentication check to reach the application's server?
Citrix released software updates to address the flaw, and Cloudflare followed with an emergency web application firewall (WAF) rule on October 1. But having a patch available Continue reading
A driver’s license tells you who someone is and that they passed a driving test, not whether they’ll drive responsibly in the future. The same is true for bots: verifying who operates it creates accountability, but trust depends on what it does next. A known bot can still ignore website preferences, overwhelm origins, or evade controls. It’s not always malicious — often it’s just a misconfiguration or a bug.
As we described in a previous blog post on bot behavior, we strive to verify two questions: “Are you who you say you are?” and “Can we trust you?” To be a Cloudflare Verified Bot, you broadly need to meet three criteria:
Bots use Web Bot Auth to sign requests that establish their identity, which BotBase then catalogues in an open format. With identification addressed, our focus shifts to the second cardinal rule of Verified bots: thou shalt do no harm.
Today we introduce a system to evaluate and report when Verified bot behavior starts to deviate from this rule, ensuring that the answer to “Can we trust you?” remains “Yes.”
Security alerts rarely arrive one at a time. A single alert can cause a spike across the environment, requiring a human analyst to decide which alerts are related and what they mean. When multiple arrive at the same time, it can quickly overwhelm even a seasoned security analyst. Enter the alert paradox. Now, our built-in, multi-AI-agent security operations harness can handle more of this work at Cloudflare scale.
Our Cloudflare Managed Defense AI agent harness speeds up the process of gathering data, connecting and aggregating detections, and accounting for missing sources while new alerts continue to arrive. To further analyze context, we make use of the OpenAI Daybreak Defense Network and our partnership with Anthropic. Cloudflare uses approved OpenAI Daybreak and Anthropic models, including GPT-5.6 Cyber and Mythos, for deeper model-backed analysis. Initial analysis and scoring is done with Clef, Cloudflare’s open-source decision model.
Collecting evidence to understand what each alert means requires a lot of time. Even in a highly sophisticated Security Information and Event Management (SIEM), too much is still left for a human to review. Human analysts must gather data, connect and aggregate detections, and account for missing sources while new alerts continue to arrive.
Think about every Continue reading
We launched Quick Tunnels in 2021 to give developers an easy way to share their latest service, application, or project running in their local development environment. A lot has changed since then, but the core use case remains the same.
Your coding agent has just finished the feature. The dev server is up on localhost:5173, and before you ask, the agent offers to let you try it on your phone. It runs one command and hands you a link:
That command starts a Quick Tunnel. cloudflared, Cloudflare's lightweight connector, publishes your local service at a random trycloudflare.com URL. No account, no domain, no cost. Agents now use Quick Tunnels for the same reason people do: they are the shortest path from a local port to a URL.
The catch has always been the same. Anyone with the link can open it.
Starting with cloudflared 2026.9.3, you can add --allowed-mail to the command, and your Quick Tunnel only lets in the email addresses and domains you choose. Visitors prove they own one of those addresses with a one-time PIN from Cloudflare Access. Nobody, on either side, needs a Cloudflare account.
Traditionally, preventing online fraud relied on point-in-time proof of identity: enter the correct password, complete a biometric verification, or pass a liveness check, and gain access. To defeat these controls, fraudsters had to steal credentials and other identity evidence from a real user, which was difficult to execute and scale. Today, widespread access to AI enables fraudsters to fabricate or imitate legitimate identities by combining exposed credentials with synthetic media designed to evade identity verification. Consequently, identity checks are no longer sufficient as they capture a moment in time. Even when someone passes a check, it does not mean the account itself can be trusted.
One convincing interaction can be faked. A consistent pattern of legitimate behavior is much harder to manufacture. Modern fraud prevention must move beyond stateless decisions toward a stateful trust model. Traditional identity verification asks, “Can this person pass the check right now?” A stateful approach additionally asks, “Does it fit what we know about this account and its established behavior?” At Cloudflare, trust is continually earned and reassessed at each interaction against historical behavioral, network, and device patterns.
Cloudflare’s Account Abuse Protection (AAP) creates stateful account overviews to help website owners detect and investigate abuse across Continue reading
It's Birthday Week, when we traditionally ship presents to the Internet. This year, two of them come from Europe: EuroLLM, which covers all 24 official EU languages, and Apertus, Switzerland's fully open model, trained on more than 1,500 languages. Both were built by public universities and research institutions. Both are coming to Workers AI, and you can request access today.
We're also launching hands-on workshops that help government cyber agencies and critical infrastructure operators build AI defenses that work with any model. The first runs in Singapore in October.
Today's announcements follow from an argument we made a year ago, when questions about AI access and sovereignty were swirling in national capitals. Our answer was choice: the freedom to pick the right tools for the job, and to switch when you need to.
Since then, those conversations have hardened. Attackers have used frontier models to run cyber attacks. Access to some frontier models now depends on where you are. Calls to restrict open models are getting louder. Put it all together and it's easy to conclude that AI sovereignty is zero-sum: every model another country controls is one you can't count on, so the safe move is to build walls.
Twelve years ago, during Birthday Week 2014, we turned on Universal SSL and nearly doubled the number of encrypted sites on the web overnight, giving free TLS to every site behind Cloudflare, including the ones that never paid us a cent. Encryption stopped being an expensive, time-intensive undertaking and instead became the default.
For Birthday Week this year, we are taking the next step on that path. For more than a decade we have been one of the largest consumers of publicly trusted certificates on the Internet, and have never issued a single one ourselves. That is changing. Cloudflare is announcing our intent to become a public certificate authority (CA).
Today we are announcing the first concrete milestones in that effort: We have applied for inclusion in the Chrome, Apple, Microsoft, and Mozilla root programs, and we have signed a definitive agreement to acquire an established, broadly trusted root from GlobalSign, so that we can offer certificates with the widest possible device reach the day we begin issuing. We’re also announcing our plans to be one of the first CAs to serve post-quantum certificates, targeting Chrome’s recently announced Quantum-resistant Root Program.
We are not issuing certificates yet, and it will be Continue reading