CVE-2026-47072

MEDIUM EPSS 39.4%
Published May 25, 20261mo ago · Modified Jun 17, 20261w ago
6.9 CVSS 4.0
Medium
Find Similar
Published May 25, 2026 1mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
6.9
Exploitability
—
Impact
—
Vector string
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/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
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
39.4% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 1

CWE-93

Affected Products 1

VendorProductVersionRange
benoitchackney*≥2.0.0  –  <4.0.1

References 4

  • cna.erlef.org https://cna.erlef.org/cves/CVE-2026-47072.html
    PatchThird Party Advisory
  • github.com https://github.com/benoitc/hackney/commit/52310ca807e7b48441ba0e9129171f535313fdd1
    Patch
  • github.com https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fg
    ExploitPatchVendor Advisory
  • osv.dev https://osv.dev/vulnerability/EEF-CVE-2026-47072
    PatchThird Party Advisory

Remediation

  • cna.erlef.org https://cna.erlef.org/cves/CVE-2026-47072.html
    PatchThird Party Advisory
  • github.com https://github.com/benoitc/hackney/commit/52310ca807e7b48441ba0e9129171f535313fdd1
    Patch
  • github.com https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fg
    ExploitPatchVendor Advisory
  • osv.dev https://osv.dev/vulnerability/EEF-CVE-2026-47072
    PatchThird Party Advisory