CVE-2026-47072: CRLF injection in WebSocket upgrade request in hackney
benoitc · hackney
Fixed in 4.0.1 · Affected: benoitc hackney before 4.0.1 · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 46% of scored CVEs
DescriptionCVE.org
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.
Affected products2
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- benoitc · hackneyfrom 2.0.0 before 4.0.1
- benoitc · hackneyVersions not stated
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CoverageNo articles yet
No CyberSIXT article names CVE-2026-47072 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.