benoitc hackney up to 4.0.0 URL Query crlf injection

Summaryinfo

A vulnerability was found in benoitc hackney up to 4.0.0. It has been classified as problematic. This impacts an unknown function of the component URL Query. Performing a manipulation results in crlf injection. This vulnerability is reported as CVE-2026-47075. The attack requires a local approach. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as problematic has been found in benoitc hackney up to 4.0.0. This affects an unknown code block of the component URL Query. The manipulation with an unknown input leads to a crlf injection vulnerability. CWE is classifying the issue as CWE-93. The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs. This is going to have an impact on integrity. The summary by CVE is:

Improper Neutralization of CRLF Sequences vulnerability in benoitc hackney allows HTTP Request Splitting. hackney does not percent-encode carriage return (\r) or line feed (\n) characters in the URL query component before constructing the HTTP/1.1 request target. Characters outside the grammar defined in RFC 3986 Section 3.4 must be percent-encoded, but hackney_url:make_url/3 passes the query binary directly without validation or escaping. An attacker who can control all or part of a URL passed to hackney can inject raw CRLF sequences into the query string, which are then sent as HTTP line breaks in the request target. This enables injection of arbitrary HTTP headers or splitting of the HTTP request. This issue affects hackney: from 0 before 4.0.1.

The weakness was disclosed by tepel-chen and Jonatan Männchen. The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-47075 since 05/18/2026. The exploitability is told to be easy. An attack has to be approached locally. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available.

Upgrading to version 4.0.1 eliminates this vulnerability. Applying the patch ca73dd0aba0ed557449c18288bf07241671a43c9 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-31687). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• benoitc

Name

• hackney

Version

• 4.0

Website

• Product: https://github.com/benoitc/hackney/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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