Request smuggling via first-wins Content-Length parsing in inets httpd
Summary
| CVE | CVE-2026-23941 |
|---|---|
| State | PUBLISHED |
| Assigner | EEF |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-13 19:54:15 UTC |
| Updated | 2026-04-06 17:17:08 UTC |
| Description | Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in Erlang OTP (inets httpd module) allows HTTP Request Smuggling. This vulnerability is associated with program files lib/inets/src/http_server/httpd_request.erl and program routines httpd_request:parse_headers/7. The server does not reject or normalize duplicate Content-Length headers. The earliest Content-Length in the request is used for body parsing while common reverse proxies (nginx, Apache httpd, Envoy) honor the last Content-Length value. This violates RFC 9112 Section 6.3 and allows front-end/back-end desynchronization, leaving attacker-controlled bytes queued as the start of the next request. This issue affects OTP from OTP 17.0 until OTP 28.4.1, OTP 27.3.4.9 and OTP 26.2.5.18, corresponding to inets from 5.10 until 9.6.1, 9.3.2.3 and 9.1.0.5. |
Risk And Classification
Primary CVSS: v4.0 7 HIGH from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:L/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
Problem Types: CWE-444 | CWE-444 CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | Secondary | 7 | HIGH | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:L/E:X/C... |
| 4.0 | CNA | CVSS | 7 | HIGH | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:L |
CVSS v4.0 Breakdown
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:L/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
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/erlang/otp/commit/a4b46336fd25aa100ac602eb9a627aaead7eda18 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| cna.erlef.org/cves/CVE-2026-23941.html | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | cna.erlef.org | |
| www.erlang.org/doc/system/versions.html | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | www.erlang.org | |
| github.com/erlang/otp/security/advisories/GHSA-w4jc-9wpv-pqh7 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| github.com/erlang/otp/commit/a761d391d8d08316cbd7d4a86733ba932b73c45b | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| osv.dev/vulnerability/EEF-CVE-2026-23941 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | osv.dev | |
| github.com/erlang/otp/commit/e775a332f623851385ab6ddb866d9b150612ddf6 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Luigino Camastra / Aisle Research (en)
CNA: Konrad Pietrzak (en)
Additional Advisory Data
Workarounds
CNA: * Configure frontend proxy to reject requests with duplicate Content-Length headers. * Disable HTTP keep-alive on httpd by adding `{keep_alive, false}` to httpd configuration. Note: This impacts performance for clients making multiple requests. * Deploy a Web Application Firewall (WAF) configured to reject requests with multiple Content-Length headers.