CRLF injection in WebSocket upgrade request in hackney_CVE-2026-47072

6.9 / 10

MEDIUM

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

Description

Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in benoitc hackney allows HTTP Request/Response Splitting. The WebSocket upgrade code in src/hackney_ws.erl copies the host, path, headers (ExtraHeaders), and protocols options from the caller-supplied opts map into the internal #ws_data{} record in init/1 and then splices them verbatim into the raw HTTP/1.1 upgrade request by binary concatenation in do_handshake/1. No CRLF or NUL stripping is performed at any of these four injection sites. An attacker who controls any of these options — for example by forwarding URL components or header values from untrusted input into hackney_ws:start_link/1 — can inject arbitrary HTTP headers into the outbound WebSocket upgrade request, leading to header injection, credential spoofing toward the upstream server, log and cache poisoning, or request smuggling via intermediary proxies.

This issue affects hackney: from 2.0.0 before 4.0.1.

Basic Information

ID CVE-2026-47072

Source EEF

Published May 25, 2026 at 14:00

Affected Product

Vendor benoitc

Product hackney

Version 2.0.0

Affected Versions benoitc hackney 2.0.0
benoitc hackney 690cecaf236fba49526da404a5bc889a24367a3e

CWE Classification

CWE-93

References

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    "published": "2026-05-25T14:00:47.852Z",
    "modified": "2026-05-25T14:00:47.852Z",
    "type": "cve",
    "title": "CRLF injection in WebSocket upgrade request in hackney",
    "source": "EEF",
    "references": "https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fg\nhttps://cna.erlef.org/cves/CVE-2026-47072.html\nhttps://osv.dev/vulnerability/EEF-CVE-2026-47072\nhttps://github.com/benoitc/hackney/commit/52310ca807e7b48441ba0e9129171f535313fdd1",
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