CR/LF injection in query parameter in hackney

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Summary

CVECVE-2026-47075
StatePUBLISHED
AssignerEEF
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-25 15:16:22 UTC
Updated2026-05-26 19:58:36 UTC
DescriptionImproper 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.

Risk And Classification

Primary CVSS: v4.0 6.8 MEDIUM from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.000210000 probability, percentile 0.062780000 (date 2026-05-27)

Problem Types: CWE-93 | CWE-93 CWE-93 Improper Neutralization of CRLF Sequences ('CRLF Injection')

VersionSourceTypeScoreSeverityVector
4.06b3ad84c-e1a6-4bf7-a703-f496b71e49dbSecondary6.8MEDIUMCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N/E:X/C...
4.0CNACVSS6.8MEDIUMCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
Active
Confidentiality
None
Integrity
High
Availability
None
Sub Conf.
None
Sub Integrity
High
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Benoitc Hackney affected 4.0.1 semver Not specified
CNA Benoitc Hackney affected 8bb1a359a81ae58567c84f8d24564e9742e6f2bd ca73dd0aba0ed557449c18288bf07241671a43c9 git Not specified

References

ReferenceSourceLinkTags
cna.erlef.org/cves/CVE-2026-47075.html 6b3ad84c-e1a6-4bf7-a703-f496b71e49db cna.erlef.org
github.com/benoitc/hackney/security/advisories/GHSA-j9wq-vxxc-94wf 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/benoitc/hackney/commit/ca73dd0aba0ed557449c18288bf07241671a43c9 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
osv.dev/vulnerability/EEF-CVE-2026-47075 6b3ad84c-e1a6-4bf7-a703-f496b71e49db osv.dev
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: tepel-chen (en)

CNA: Benoit Chesneau (en)

CNA: Jonatan Männchen (en)

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