CVE-2026-47072
CRLF injection in WebSocket upgrade request in hackney
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.
INFO
Published Date :
May 25, 2026, 3:16 p.m.
Last Modified :
May 28, 2026, 8:27 p.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update hackney to version 4.0.1 or later.
- Apply vendor-supplied patches for affected versions.
- Sanitize all user-supplied input for headers.
- Validate host, path, and protocol options.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-47072.
| URL | Resource |
|---|---|
| https://cna.erlef.org/cves/CVE-2026-47072.html | Patch Third Party Advisory |
| https://github.com/benoitc/hackney/commit/52310ca807e7b48441ba0e9129171f535313fdd1 | Patch |
| https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fg | Exploit Patch Vendor Advisory |
| https://osv.dev/vulnerability/EEF-CVE-2026-47072 | Patch Third Party Advisory |
| https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fg | Exploit Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-47072 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-47072
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-47072 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-47072 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
May. 28, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Added CPE Configuration OR *cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:* versions from (including) 2.0.0 up to (excluding) 4.0.1 Added Reference Type EEF: https://cna.erlef.org/cves/CVE-2026-47072.html Types: Patch, Third Party Advisory Added Reference Type EEF: https://github.com/benoitc/hackney/commit/52310ca807e7b48441ba0e9129171f535313fdd1 Types: Patch Added Reference Type CISA-ADP: https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fg Types: Exploit, Patch, Vendor Advisory Added Reference Type EEF: https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fg Types: Exploit, Patch, Vendor Advisory Added Reference Type EEF: https://osv.dev/vulnerability/EEF-CVE-2026-47072 Types: Patch, Third Party Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 26, 2026
Action Type Old Value New Value Added Reference https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fg -
New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
May. 25, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/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 Added CWE CWE-93 Added Reference https://cna.erlef.org/cves/CVE-2026-47072.html Added Reference https://github.com/benoitc/hackney/commit/52310ca807e7b48441ba0e9129171f535313fdd1 Added Reference https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fg Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-47072