Cloudflare blocks largest recorded DDoS attack peaking at 11.5 Tbps

Cloudflare has said it recently blocked the largest recorded volumetric DDoS attack, peaking at 11.5 Tbps, with the incident lasting around 35 seconds and predominantly sourced from Google Cloud in a UDP flood. According to Cloudflare, the company has been blocking hundreds of hyper-volumetric DDoS attacks in recent weeks, the largest reaching 11.5 Tbps, and notes this came two months after a separate 7.3 Tbps attack targeting an unnamed hosting provider in June.

The earlier record stood at 3.8 Tbps, accompanied by two billion packets per second, which Cloudflare also mitigated in October 2024. In its 2025 Q1 DDoS Report, Cloudflare disclosed a record number of DDoS incidents mitigated in 2024, including a 358% year‑over‑year rise and a 198% quarter‑over‑quarter increase, with 21.3 million attacks against Cloudflare customers last year. The update appeared in a publication dated 2 September 2025.