CVE-2026-67181

MEDIUM 5.4

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

CVSS Score

5.4

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-444
Vendor	tomaka
Product	rouille
Published	Jul 28, 2026
Last Updated	Jul 28, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:L

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

Low

Availability

Low

Affected Versions

tomaka / rouille

0.3.3 ≤ 3.6.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/theopaid/HTTP-Request-Smuggling-via-Transfer-Encoding-Desynchronization-rouille- vulncheck.com: https://www.vulncheck.com/advisories/rouille-http-request-smuggling-via-proxy-transfer-encoding-header

Credits

Theodosis Paidakis