Weakness Type (CWE)

CWE-93 — CWE-93 Improper Neutralization of CRLF Sequences ('CRLF Injection')

CAPEC

CVSS 4.0 Score

6.8

MEDIUM

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N

Vulnerability description

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.

Affected

pkg:hex/hackney

Module Source File Routine
hackney_url src/hackney_url.erl hackney_url:make_url/3
Status Type Version Changes / Fixed in
affected semver ⓘ initial < 4.0.1

pkg:github/benoitc/hackney

Module Source File Routine
hackney_url src/hackney_url.erl hackney_url:make_url/3
Status Type Version Changes / Fixed in
affected git ⓘ 8bb1a359a8 < ca73dd0aba

References

Credits

  • Finder: tepel-chen
  • Remediation developer: Benoit Chesneau
  • Analyst: Jonatan Männchen / EEF

CVE record as JSON:  GET /cves/CVE-2026-47075.json
OSV record as JSON:  GET /osv/EEF-CVE-2026-47075.json