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Medium · 6.8 CVE-2026-47075 EEF-CVE-2026-47075EUVD-2026-31687GHSA-j9wq-vxxc-94wf

CR/LF injection in query parameter in hackney

Published May 25, 2026 · Updated Jul 24, 2026 · Assigned by EEF

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 0.13.1 before 4.0.1.

Affected products

VendorProductAffectedFixed
benoitc hackney 0.13.1 – < 4.0.1 4.0.1

Affected packages

EcosystemPackageAffectedFixedRecord
Hex hackney >= 0.13.1, < 4.0.1 4.0.1 EEF-CVE-2026-47075
Hex hackney < 4.0.1 4.0.1 GHSA-j9wq-vxxc-94wf

References