Security | Threat Detection | Cyberattacks | DevSecOps | Compliance

Every time Cloudflare opens a new TLS 1.3 connection to an origin server, we have to make a guess: the protocol requires us to commit to a key agreement algorithm in the very first packet we send, before the origin has told us anything about itself or what it can support. If we guess right, the handshake completes in one round trip. Guess wrong, and the origin replies with a HelloRetryRequest, we start over, and the connection costs two round trips.

Your scanner just flagged 4,000 new vulnerabilities, 78 of them critical. Which one do you fix first? To answer that question, Cloudflare is announcing early access to Vulnerability Discovery and Remediation, now part of Cloudflare Managed Defense. Vulnerability Discovery and Remediation is a new, invitation-only Cloudflare service that helps customers detect and mitigate vulnerabilities in their codebases.

Modern bot threats are increasingly driven by determined, sophisticated attackers. Often it is not even one person, but a group trading techniques with each other or a commercial service sold to anyone willing to pay. For many of them, getting past bot detection is a full-time job they genuinely enjoy. Block them and they get to work, finding a workaround. AI has simplified this further, making it even easier to set up complex configurations for attackers, lowering the overhead of an attack.

Since June, developers have created thousands of third-party OAuth apps on Cloudflare, with more than a million authorizations since. OAuth makes delegated access possible. It lets applications act on a user’s behalf without asking them to handle long-lived credentials or hand over a password. That model works well when an application can describe its access needs with a small set of scopes. Developers use OAuth for SaaS integrations, internal tools, CLIs, and agents.

In 2021, we assessed remote Spectre attacks against Cloudflare Workers. Based on the results, we shipped a production defense called Dynamic Process Isolation (DyPrIs), which identifies maliciously looking scripts and isolates them into separate processes. Since then, newer techniques in the area of stabilizing Spectre attacks have been discovered. To understand if these techniques posed a threat to our Workers production environment, we decided to internally reassess the remote Spectre attack.

Route leaks push traffic down paths it was never meant to take. We have written and spoken publicly in the past about route leaks in Border Gateway Protocol (BGP), depicting these events as impactful incidents that cause misdirection of traffic through unintended network paths. BGP routing is driven by the relationships between Autonomous Systems (ASes), i.e., customer-provider and peer-peer.

AI has enabled employees across every team to build applications faster than ever before. But that speed is also what's keeping every CISO up at night: any employee can build an application, deploy it to the public Internet, and accidentally expose internal work or company data. Today, we're launching new tools to make it easy to keep your applications hosted on Workers private.

Most companies designed their resource permissions with a human user in mind. A senior engineer may be able to deploy to production, query a sensitive database, or revoke another user's access. Those privileges come with risk, but that risk has traditionally been bounded by two assumptions: the engineer will use human judgment, and the engineer can only act at human speed.

Since we launched Certificate Transparency Monitoring in public beta in 2019, we've been emailing subscribers whenever a new TLS certificate appears in a public Certificate Transparency (CT) log for one of their domains. Today, it's turned on for more than 650,000 customer domains. It's an early warning that someone, somewhere, has issued a certificate for a hostname in your zone, giving you a chance to spot a mis-issued certificate early.

Welcome to the 25th edition of Cloudflare's DDoS Threat Report. This is the first half-year edition in the series: rather than publishing separate reports for the first and second quarters of 2026, we have combined our coverage of Q1 and Q2 into a single volume covering January through June 2026.