What is http request smuggling?
HTTP Request Smuggling is a security vulnerability that arises from the incorrect processing of HTTP requests between multiple HTTP servers and proxies
Azərbaycanca: HTTP tələbi qaçaqmalı (HTTP Request Smuggling) - bir neçə HTTP server və proksi arasında HTTP tələblərinin yanlış işlənməsi nəticəsində ortaya çıxan təhlükəsizlik zəifliyi
How it works
An attacker can exploit this vulnerability by sending HTTP requests in such a way that servers and proxies process them differently. This can lead to bypassing security controls or even more severe attacks like RCE (Remote Code Execution)
Defense checklist5
- 01
Update HTTP servers and proxies to the latest versions
- 02
Configure servers and proxies to ensure correct processing of HTTP requests
- 03
Ensure HTTP/1.1 parsers do not accept both Content-Length and Transfer-Encoding: chunked headers simultaneously
- 04
Conduct security audits and penetration testing
- 05
Stay informed about security updates and CVEs
Real-world evidence
CVE-2026-67181 (Rouille 0.3.3 through 3.6.2), CVE-2026-15328 (IBM WebSphere Application Server), CVE-2026-73051 (actix-http versions before 3.12.1), and other incidents demonstrate the reality of such attacks
Sources
- CVE-2026-67181: Rouille 0.3.3 through 3.6.2 contains an HTTP request smuggling vulnerability that allows rnvd
- CVE-2026-15328: IBM WebSphere Application Server 9.0, and 8.5 and IBM WebSphere Application Server - Libernvd
- CVE-2026-15325: IBM WebSphere Application Server 9.0, and 8.5 and IBM WebSphere Application Server - Libernvd
- HTTP Request Smuggling in Hiawathar_netsec
- CVE-2026-59898: Netty is an asynchronous, event-driven network application framework. Prior to versions 4nvd
- CVE-2026-73051: actix-http versions before 3.12.1 contain an HTTP request smuggling vulnerability in the Hnvd
Other attack types
See also6
This guide is AI-written from the real incident sources skopnix collected — the examples above are drawn from those cited items, nothing is invented.