CVE-2026-67181
MediumCVSS 5.4Exploitation Probability (EPSS)
Low risk21th percentile - higher than 21% of all known CVEs
Summary
Rouille versions 0.3.3 through 3.6.2 contain an HTTP request smuggling vulnerability. The proxy implementation 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.
Risk Assessment
An attacker can manipulate HTTP message boundaries, potentially leading to session hijacking, access control bypass, or cache poisoning.
Recommendation
Update the Rouille library to version 3.6.3 or later that fixes this vulnerability, or apply a workaround by disabling the proxy functionality.
Other vulnerabilities in Rouille
See all- CVE-2026-67182High
Rouille versions 0.3.3 through 3.6.2 have an HTTP request smuggling vulnerability allowing remote attackers to bypass access controls by injecting bare line feed characters (0x0A) into client-supplied header values. These values are copied verbatim to upstream connections without validation. Attackers can craft a header containing an additional HTTP request interpreted as separate by backends (e.g., Go net/http, Python http.server), bypassing Rouille's access control logic.
- CVE-2026-66754Medium
Rouille versions 0.1.6 through 3.6.2 contain a reachable assertion vulnerability in the Request::remove_prefix function that allows remote unauthenticated attackers to crash the server by sending a crafted percent-encoded URL.
- CVE-2026-66746Medium
Rouille versions 0.4.0 through 3.6.2 contain an HTTP response splitting vulnerability that allows remote attackers to inject arbitrary response headers by embedding carriage return (0x0D) or line feed (0x0A) bytes into attacker-controlled input.
Original NVD description (English source)
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.