HTTP Request Smuggling Vulnerability in Rouille Proxy Implementation
CVE-2026-67181

6.3MEDIUM

Key Information:

Vendor

Tomaka

Status
Rouille
Vendor
CVE Published:
28 July 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-67181?

Rouille, a HTTP server framework, has a vulnerability in versions 0.3.3 through 3.6.2 that allows remote attackers to exploit improper header forwarding in its proxy implementation. This flaw occurs when the proxy forwards the client's Transfer-Encoding header to upstream servers without proper modification, even after the request body has already been de-chunked. This can lead to CL.TE desynchronization attacks, enabling attackers to manipulate HTTP message boundaries and potentially generate unauthorized requests on backend servers.

Affected Version(s)

rouille 0.3.3 <= 3.6.2

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-67181 - Proof of Concept

References

https://github.com/theopaid/HTTP-Request-Smuggling-via-Tr...
technical-descriptionexploit
https://www.vulncheck.com/advisories/rouille-http-request...
third-party-advisory

CVSS V4

Score:
6.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Theodosis Paidakis
.