Internet infrastructure giant Cloudflare has announced it successfully mitigated the largest recorded volumetric distributed denial-of-service (DDoS) attack in history.

The unprecedented attack, which also reached a rate of 5.1 billion packets per second (Bpps), marks a significant escalation in the scale and power of DDoS threats. Volumetric DDoS attacks function by overwhelming a target with a tsunami of malicious traffic, consuming bandwidth and exhausting system resources to deny access to legitimate users.

In a post on X, the company stated: “Cloudflare’s defenses have been working overtime. Over the past few weeks, we’ve autonomously blocked hundreds of hyper-volumetric DDoS attacks, with the largest reaching peaks of 5.1 Bpps and 11.5 Tbps.”

Cloudflare initially reported that the 11.5 Tbps UDP flood attack lasted approximately 35 seconds and primarily originated from Google Cloud. However, the company later issued a correction, clarifying that the “attack in fact came from a combination of several IoT and cloud providers.”

UPDATE: The 11.5 Tbps attack in fact came from a combination of several IoT and cloud providers. While Google Cloud was one source, it was not the majority. Stay tuned for a full breakdown in our next report. https://t.co/MOBVRmmPqW

— Cloudflare (@Cloudflare) September 2, 2025

This incident occurs just two months after Cloudflare announced it had blocked another record-breaking 7.3 Tbps DDoS attack targeting an unnamed hosting provider in June. The previous record before that was a 3.8 Tbps attack mitigated by Cloudflare in October 2024.

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The news follows a trend of increasingly powerful attacks. Microsoft mitigated a 3.47 Tbps volumetric DDoS attack targeting an Azure customer in January 2022, and another massive attack disrupted multiple Microsoft 365 and Azure services worldwide in July 2024.

Cloudflare’s recent DDoS report for Q1 2025 revealed it mitigated a record number of attacks in 2024, noting a 198% quarter-over-quarter increase and a 358% year-over-year jump. The company stated it mitigated a total of 21.3 million DDoS attacks that targeted its customers last year, as well as 6.6 million attacks targeting its own infrastructure during an 18-day multi-vector campaign.