CVE-2026-67181

Rouille 0.3.3 - 3.6.2 HTTP Request Smuggling via proxy Transfer-Encoding Header

MEDIUM
5.4
CVSS Score
Published: July 28, 2026 at 04:10 PM UTC
Updated: October 24, 2026 at 01:10 PM UTC
1 product affected across 1 vendorRouille

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.4%
SSVC
PoC

Description

Rouille 0.3.3 through 3.6.2 contains an HTTP request smuggling vulnerability that allows remote attackers to desynchronize HTTP message boundaries by exploiting improper header forwarding in the proxy implementation. The proxy in src/proxy.rs forwards the client's Transfer-Encoding header to upstream backends unchanged while transmitting a body already de-chunked by tiny_http, enabling CL.TE desynchronization attacks where attackers control where the backend believes the request body ends.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.3.3 ≤ v ≤ 3.6.20.3.3

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.4MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-444

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