HTTP Request Smuggler
Summary: PortSwigger released version 3.0 of its HTTP Request Smuggler extension in 2025, adding parser discrepancy detection that the vendor says bypasses widespread desync defences. The extension detects and exploits HTTP Request Smuggling using desynchronization techniques developed by researcher James Kettle, covering HTTP/1.1 and HTTP/2-downgrade desyncs, client-side desyncs, and connection state attacks.
What you should know: A tool that automates bypassing the defences organizations already deployed against request smuggling means those parser-level protections may no longer hold, and the extension is freely available to attackers as well as testers.
Read the original at PortSwigger Research ↗
- Topics
- Vulnerabilities & Patching
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