Vulnerability in Benoitc Hackney
CVE-2026-47072
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.
Vulnerability class: CRLF Injection
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.005 (42.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 42.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: -0.000
Affected products
- Benoitc Hackney — versions 2.0.0, 690cecaf236fba49526da404a5bc889a24367a3e
Weakness classification (CWE)
References
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, Exploit, vendor-advisory, Patch, Vendor Advisory)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, Patch, Third Party Advisory)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, Patch, Third Party Advisory)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Patch, patch)
Frequently asked questions
- What is CVE-2026-47072?
- CVE-2026-47072 is a high-severity vulnerability in Benoitc Hackney, classified under CRLF Injection. CVSS score: 7.5/10. Published 2026-05-25.
- How severe is CVE-2026-47072?
- High severity. CVSS v3 base score is 7.5 out of 10.