---
id: CVE-2026-23941
title: >-
  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_…
summary: >-
  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_…
severity: critical
cvss: 9.4
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L'
cwe:
  - CWE-444
vendor: erlang
product: erlang/inets
affected:
  - 'erlang/inets >= 5.10, < 9.1.0.5'
  - 'erlang/inets >= 9.3, < 9.3.2.3'
  - 'erlang/inets >= 9.6, < 9.6.1'
  - 'erlang/otp >= 17.0, < 26.2.5.18'
  - 'erlang/otp >= 27.0, < 27.3.4.9'
  - 'erlang/otp >= 28.0, < 28.4.1'
patched:
  - erlang/inets 9.6.1
  - erlang/otp 28.4.1
published: '2026-03-13'
updated: '2026-07-24'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-23941'
references:
  - url: 'https://cna.erlef.org/cves/CVE-2026-23941.html'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/erlang/otp/commit/a4b46336fd25aa100ac602eb9a627aaead7eda18
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/erlang/otp/commit/a761d391d8d08316cbd7d4a86733ba932b73c45b
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/erlang/otp/commit/e775a332f623851385ab6ddb866d9b150612ddf6
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://github.com/erlang/otp/security/advisories/GHSA-w4jc-9wpv-pqh7'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-23941'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://www.erlang.org/doc/system/versions.html#order-of-versions'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
tags:
  - nvd
epss: 0.00453
epssPercentile: 0.36699
ingestedAt: '2026-07-24T15:30:58.169Z'
---

## Overview

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 before OTP 28.4.1, OTP 27.3.4.9 and OTP 26.2.5.18, corresponding to inets from 5.10 before 9.6.1, 9.3.2.3 and 9.1.0.5.

## Affected

- `erlang/inets >= 5.10, < 9.1.0.5`
- `erlang/inets >= 9.3, < 9.3.2.3`
- `erlang/inets >= 9.6, < 9.6.1`
- `erlang/otp >= 17.0, < 26.2.5.18`
- `erlang/otp >= 27.0, < 27.3.4.9`
- `erlang/otp >= 28.0, < 28.4.1`

## Remediation

Upgrade past the affected range:

- `erlang/inets 9.6.1`
- `erlang/otp 28.4.1`