# CVE-2026-47075: benoitc hackney HTTP request splitting via CRLF injection in query string

Source: https://junglewise.ai/threats/cve-2026-47075-benoitc-hackney-http-request-splitting-via-crlf-injection-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-25. Updated: 2026-06-26  
License: CC BY 4.0 with a link back

CVE-2026-47075 · Severity: medium · CVSS 6.8 · Published 2026-05-25

Hackney, a popular HTTP client library for Erlang, contains a vulnerability that allows attackers to inject malicious data into web requests. By including special characters in a URL, an attacker can trick the library into sending unauthorized commands or headers to a server. This could lead to unauthorized access to data or the ability to bypass security controls on web proxies and servers.

## Quick answers

**Is CVE-2026-47075 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-47075 being exploited in the wild.

**How severe is CVE-2026-47075?** Medium severity, with a CVSS score of 6.8, published 25 May 2026.

**Which products and versions are affected?** benoitc hackney < 4.0.1.

**Is there a fix for CVE-2026-47075?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-47075 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-47075?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The `hackney_url:make_url/3` function in `src/hackney_url.erl` fails to percent-encode `\r` or `\n` characters in the query component of a URL. Because these characters are passed verbatim into the HTTP/1.1 request line, an attacker can terminate the request line prematurely and inject arbitrary HTTP headers or split the request into multiple distinct requests. This CRLF injection vulnerability can be exploited if an application passes attacker-controlled URL components to Hackney without prior sanitization. The issue is resolved in version 4.0.1.

## Affected products

- benoitc hackney < 4.0.1

## Identifiers

- CVE-2026-47075
- GHSA-j9wq-vxxc-94wf

## Timeline

- 2026-05-25: disclosed
- 2026-06-26: advisory: GitHub Advisory published

## References

- [https://api.github.com/users/tepel-chen](https://api.github.com/users/tepel-chen)
- [https://github.com/tepel-chen](https://github.com/tepel-chen)
- [https://api.github.com/users/tepel-chen/gists%7B/gist_id%7D](https://api.github.com/users/tepel-chen/gists%7B/gist_id%7D)
- [https://api.github.com/users/tepel-chen/repos](https://api.github.com/users/tepel-chen/repos)
- [https://avatars.githubusercontent.com/u/71225775?v=4](https://avatars.githubusercontent.com/u/71225775?v=4)
- [https://api.github.com/users/tepel-chen/events%7B/privacy%7D](https://api.github.com/users/tepel-chen/events%7B/privacy%7D)