On Monday 15 June 2026 at 00:35 UTC, a HTTP/2 rapid reset targeted a sports betting customer in Central Europe. The attack peaked at 413.0 million requests per second and lasted 50 minutes. Traffic originated from 2602 autonomous systems in 10 countries, predominantly misconfigured open reflectors.
| Vector | HTTP/2 rapid reset |
| Peak | 413.0 million requests per second |
| Duration | 50 min |
| Time to mitigation | 0.757 s |
| Attack traffic reaching origin | 0.028% |
| Legitimate traffic challenged | 0.21% |
Timeline
The attack was preceded by an extortion email received two days earlier. Request rates on the targeted routes exceeded their hourly baseline by a factor of 787 within 21 seconds. The risk score of participating clients crossed the challenge threshold automatically and proof-of-work difficulty rose with origin load.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Review allow-listed partner ranges quarterly.
Interesting that most attacks are under ten minutes. Our experience is similar.
Great to hear, thanks for sharing your experience.
The billing model is what got our finance team on board, honestly.
Nice to read a vendor blog that admits what went wrong.
Any plans to support per-tenant limits keyed on a JWT claim?
Clear and practical, thanks.
The point about origin IPs leaking through certificate transparency logs is underrated.
The point about origin IPs leaking through certificate transparency logs is underrated.