Vulnerability 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 Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Benoitc | Hackney | >= 2.0.0, < 4.0.1 |
Related Weaknesses (CWE)
References
- https://cna.erlef.org/cves/CVE-2026-47072.htmlPatchThird Party Advisory
- https://github.com/benoitc/hackney/commit/52310ca807e7b48441ba0e9129171f535313fdPatch
- https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fgExploitPatchVendor Advisory
- https://osv.dev/vulnerability/EEF-CVE-2026-47072PatchThird Party Advisory
- https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fgExploitPatchVendor Advisory
FAQ
What is CVE-2026-47072?
CVE-2026-47072 is a vulnerability with a CVSS score of 7.5 (HIGH). 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, ...
How severe is CVE-2026-47072?
CVE-2026-47072 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-47072?
Check the references section above for vendor advisories and patch information. Affected products include: Benoitc Hackney.