HTTP/2 Bomb — Remote DoS Exploit Hits nginx, Apache, IIS, Envoy, and Cloudflare Pingora

Cybersecuritynews •Guru Baran • June 3, 2026

A newly disclosed remote denial-of-service exploit dubbed “HTTP/2 Bomb” targets the default HTTP/2 configurations of the world’s most widely deployed web servers, nginx, Apache httpd, Microsoft IIS, Envoy, and Cloudflare Pingora, enabling a single attacker on a internet connection to exhaust tens of gigabytes of server memory in seconds. The exploit was discovered by […]

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

New HTTP/2 Bomb DoS Attack Crashes Major Web Servers The HTTP/2 Bomb is a newly discovered denial-of-service (DoS) attack that targets default configurations of major web servers, including NGINX, Apache, Microsoft IIS, Envoy, and Cloudflare Pingora. This attack, identified by researchers at Calif and OpenAI's Codex, exploits the HPACK header compression mechanism and employs a zero-byte flow-control window to prevent memory from being released. A single attacker can exhaust tens of gigabytes of server memory in seconds, rendering the server inaccessible. Proof-of-concept exploits have been published, and while some platforms have released patches, many remain vulnerable. The full technical details will be presented at the Real World AI Security conference later this month. 11 sources 69

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HTTP/2 Bomb — Remote DoS Exploit Hits nginx, Apache, IIS, Envoy, and Cloudflare Pingora

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