CVE-2026-47072: Benoitc Hackney vulnerability (CVSS 7.5)

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 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityNone

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

Benoitc Hackney≥ 2.0.0 < 4.0.1

Remediation

Fixed in

Benoitc Hackney≥ 4.0.1

Patch & vendor advisories

References

https://cna.erlef.org/cves/CVE-2026-47072.htmlPatchThird Party Advisory
https://github.com/benoitc/hackney/commit/52310ca807e7b48441ba0e9129171f535313fdd1Patch
https://github.com/benoitc/hackney/security/advisories/GHSA-f9vr-g2g2-x9fgExploitPatchVendor Advisory
https://osv.dev/vulnerability/EEF-CVE-2026-47072PatchThird Party Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2026-47072 being actively exploited?

CVE-2026-47072 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.52%.

How severe is CVE-2026-47072?

CVE-2026-47072 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.52% probability of exploitation.

Which products are affected by CVE-2026-47072?

Affected products include Benoitc Hackney.

How do I fix CVE-2026-47072?

Upgrade affected software to a fixed version, for example Benoitc Hackney 4.0.1 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-47072 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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