Riskcovery

CVE-2026-23941

Request smuggling via first-wins Content-Length parsing in inets httpd

State
Published
Severity
7.0 High
Published
Mar 13, 2026
Updated
Jul 24, 2026
Reserved
Jan 19, 2026

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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 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.

Scores

CVSSScoreVectorSource
4.07.0 HighCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:LEEF

Weaknesses

  • CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')

Affected Products

ProductVersions
OTPErlang
  • 5.10 and laterAffectedfrom 9.6.1Not affectedfrom 9.3.2.3Not affectedfrom 9.1.0.5Not affected
OTPErlang
  • 17.0 and laterAffectedfrom 28.4.1Not affectedfrom 27.3.4.9Not affectedfrom 26.2.5.18Not affected
  • 84adefa331c4159d432d22840663c38f155cd4c1 and laterAffectedfrom a4b46336fd25aa100ac602eb9a627aaead7eda18Not affectedfrom a761d391d8d08316cbd7d4a86733ba932b73c45bNot affectedfrom e775a332f623851385ab6ddb866d9b150612ddf6Not affected

References

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