HTTP/1.1 Must Die: What This Means for Bug Bounty Hunters
Summary: At Black Hat USA and DEFCON 2025, PortSwigger Director of Research James Kettle presented research titled HTTP/1.1 Must Die: The Desync Endgame, arguing that HTTP request smuggling (desync) attacks remain widespread and compromise tens of millions of websites. Kettle and his team collected over $200k in bug bounties in about two weeks, and the research describes one finding that gave control over 24 million websites via CDN cache poisoning.
What's compelling: The research argues that patching individual implementations will never eliminate request smuggling and that upstream HTTP/2 is the robust fix, which puts the flaw in the protocol layer between CDNs, load balancers, and backend servers rather than in any single application. A single parser mismatch that yielded control over 24 million sites through CDN cache poisoning shows how far one subtle discrepancy can reach.
Read the original at PortSwigger Research ↗
- Topics
- Vulnerabilities & Patching
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