Erlang OTP RFC 9112 httpd_request.erl Content-Length request smuggling

Summaryinfo

A vulnerability classified as problematic has been found in Erlang OTP. This affects an unknown part in the library lib/inets/src/http_server/httpd_request.erl of the component RFC 9112. The manipulation of the argument Content-Length leads to request smuggling. This vulnerability is referenced as CVE-2026-23941. Remote exploitation of the attack is possible. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Erlang OTP (version now known) and classified as problematic. This issue affects some unknown processing in the library lib/inets/src/http_server/httpd_request.erl of the component RFC 9112. The manipulation of the argument Content-Length with an unknown input leads to a request smuggling vulnerability. Using CWE to declare the problem leads to CWE-444. The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-23941 since 01/19/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 302363 (Linux Distros Unpatched Vulnerability : CVE-2026-23941), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (302363) and CERT Bund (WID-SEC-2026-0721). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• SUSE openSUSE
• Open Source Erlang/OTP

Productinfo

Vendor

• Erlang

Name

• OTP

Website

• Product: https://github.com/erlang/otp/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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