Hackney · Hackney · CVE-2026-47075
**Name of the Vulnerable Software and Affected Versions**
hackney versions 0 through 4.0.0
**Description**
Improper Neutralization of CRLF Sequences allows HTTP Request Splitting. The software fails to percent-encode carriage return (`r`) or line feed (`
`) characters in the URL query component before constructing the HTTP/1.1 request target. Specifically, the `hackney url:make url/3` function passes the query binary directly without validation or escaping, violating RFC 3986 Section 3.4. An attacker controlling part of a URL can inject raw CRLF sequences into the query string, enabling the injection of arbitrary HTTP headers or the splitting of the HTTP request.
**Recommendations**
Update to version 4.0.1.