CVE-2026-67181: tomaka rouille HTTP Request/Response Smuggling

Vulnerability summary

CVE-2026-67181 is a medium (CVSS 6.3) HTTP Request/Response Smuggling vulnerability in tomaka rouille. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 34.6% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 28-07-2026
   PublishedVulnerability first disclosed.
2. 28-07-2026
   Last modifiedVulnerability information updated.

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.

• CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.