CVE-2026-47069Public exploitNetwork attack vector

HTTP response splitting via unvalidated cookie options

Published May 25, 2026 · Updated May 25, 2026

CRLF injection in hackney 0.9.0 through 4.0.0 allows attackers to split HTTP responses through crafted cookie options. hackney_cookie:setcookie/3 validates cookie names and values but appends domain and path options verbatim, allowing CRLF bytes to create additional Set-Cookie headers. Exploitation requires attacker-controlled data to reach either option; successful injection can overwrite session or authentication cookies.

CVSS severity5.3
Medium
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CRLF injection in hackney 0.9.0 through 4.0.0 allows attackers to split HTTP responses through crafted cookie options. hackney_cookie:setcookie/3 validates cookie names and values but appends domain and path options verbatim, allowing CRLF bytes to create additional Set-Cookie headers. Exploitation requires attacker-controlled data to reach either option; successful injection can overwrite session or authentication cookies.

The record

CVE
CVE-2026-47069
Published
May 25, 2026
Updated
May 25, 2026
Vendor
Benoit Chesneau
Product
Hackney
Classifications
CWE-93, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 25, 2026CVE publishedPublication date reported by the CVE source.
  2. May 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.9.0 <4.0.1
  2. Affected versionversion=602d5c7f2ea4acbc83ed75230655d935a0750ebc <8e02b99c28aea1b3fa2ddc0e66f51fe5bb0ac540

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Benoit Chesneau · Hackneyversion=0.9.0 <4.0.1; version=602d5c7f2ea4acbc83ed75230655d935a0750ebc <8e02b99c28aea1b3fa2ddc0e66f51fe5bb0ac540

Published CVSS scores

5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
2.1Erlang Ecosystem FoundationCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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