CWE-444
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
BaseIncomplete
Description
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.
Hierarchy (View 1000)
Parents
Children
none
Related attack patterns (CAPEC)
CAPEC-273 · CAPEC-33
CVEs mapped to this weakness (70)
page 2 of 4| CVE | Sev | Risk | CVSS | EPSS | KEV | Published | Description |
|---|---|---|---|---|---|---|---|
| CVE-2024-6827 | Hig | 0.49 | 7.5 | 0.00 | Mar 20, 2025 | Gunicorn version 21.2.0 does not properly validate the value of the 'Transfer-Encoding' header as specified in the RFC standards, which leads to the default fallback method of 'Content-Length,' making it vulnerable to TE.CL request smuggling. This vulnerability can lead to cache poisoning, data exposure, session manipulation, SSRF, XSS, DoS, data integrity compromise, security bypass, information leakage, and business logic abuse. | |
| CVE-2024-44775 | Hig | 0.49 | 7.5 | 0.01 | Oct 15, 2024 | kmqtt v0.2.7 is vulnerable to Denial of Service (DoS) due to a Null Pointer Exception. A remote attacker can cause the broker to crash by sending a specially crafted MQTT CONNECT packet that triggers an unhandled null reference, leading to an immediate process termination. | |
| CVE-2017-7561 | Hig | 0.49 | 7.5 | 0.01 | Sep 13, 2017 | Red Hat JBoss EAP version 3.0.7 through before 4.0.0.Beta1 is vulnerable to a server-side cache poisoning or CORS requests in the JAX-RS component resulting in a moderate impact. | |
| CVE-2026-2332 | Hig | 0.48 | 7.4 | 0.00 | Apr 14, 2026 | In Eclipse Jetty, the HTTP/1.1 parser is vulnerable to request smuggling when chunk extensions are used, similar to the "funky chunks" techniques outlined here: * https://w4ke.info/2025/06/18/funky-chunks.html * https://w4ke.info/2025/10/29/funky-chunks-2.html Jetty terminates chunk extension parsing at \r\n inside quoted strings instead of treating this as an error. POST / HTTP/1.1 Host: localhost Transfer-Encoding: chunked 1;ext="val X 0 GET /smuggled HTTP/1.1 ... Note how the chunk extension does not close the double quotes, and it is able to inject a smuggled request. | |
| CVE-2026-42584 | Hig | 0.47 | 7.3 | 0.00 | May 13, 2026 | Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpClientCodec pairs each inbound response with an outbound request by queue.poll() once per response, including for 1xx. If the client pipelines GET then HEAD and the server sends 103, then 200 with GET body, then 200 for HEAD, the queue pairs HEAD with the first 200. The HEAD rule then skips reading that message’s body, so the GET entity bytes stay on the stream and the following 200 is parsed from the wrong offset. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final. | |
| CVE-2024-41671 | Hig | 0.47 | 8.3 | 0.00 | Jul 29, 2024 | Twisted is an event-based framework for internet applications, supporting Python 3.6+. The HTTP 1.0 and 1.1 server provided by twisted.web could process pipelined HTTP requests out-of-order, possibly resulting in information disclosure. This vulnerability is fixed in 24.7.0rc1. | |
| CVE-2026-23941 | Hig | 0.46 | — | 0.00 | Mar 13, 2026 | 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. | |
| CVE-2025-12811 | Med | 0.45 | — | 0.00 | Feb 18, 2026 | Improper Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') in Delinea Inc. Cloud Suite and Privileged Access Service. If you're not using the latest Server Suite agents, this fix requires that you upgrade to Server Suite 2023.1 (agent 6.0.1) or later. * If you cannot upgrade to Release 2023.1 (agent version 6.0.1) or later, you can choose one of the following versions: * Server Suite release 2023.0.5 (agent version 6.0.0-158) * Server Suite release 2022.1.10 (agent version 5.9.1-337) | |
| CVE-2025-41082 | Med | 0.45 | — | 0.00 | Jan 26, 2026 | Illegal HTTP request traffic vulnerability (CL.0) in Altitude Communication Server, caused by inconsistent analysis of multiple HTTP requests over a single Keep-Alive connection using Content-Length headers. This can cause a desynchronization of requests between frontend and backend servers, which could allow request hiding, cache poisoning or security bypass. | |
| CVE-2023-53878 | Med | 0.45 | — | 0.00 | Dec 15, 2025 | Member Login Script 3.3 contains a client-side desynchronization vulnerability that allows attackers to manipulate HTTP request handling by exploiting Content-Length header parsing. Attackers can send crafted POST requests with smuggled secondary requests to potentially bypass server-side request processing controls. | |
| CVE-2025-11915 | Med | 0.45 | — | 0.00 | Oct 22, 2025 | Connection desynchronization between an HTTP proxy and the model backend. The fixes were rolled out for all proxies in front of impacted models by 2025-09-28. Users do not need to take any action. | |
| CVE-2025-6999 | Med | 0.45 | — | 0.00 | Sep 15, 2025 | An HTTP Request Smuggling [CWE-444] vulnerability in the Authentication portal of WatchGuard Fireware OS allows a remote attacker to evade request parameter sanitation and perform a reflected self-Cross-Site Scripting (XSS) attack.This issue affects Fireware OS: from 12.0 through 12.11.2. | |
| CVE-2024-56908 | Med | 0.44 | 6.8 | 0.00 | Feb 13, 2025 | In Perfex Crm < 3.2.1, an authenticated attacker can send a crafted HTTP POST request to the affected upload_sales_file endpoint. By providing malicious input in the rel_id parameter, combined with improper input validation, the attacker can bypass restrictions and upload arbitrary files to directories of their choice, potentially leading to remote code execution or server compromise. | |
| CVE-2026-42585 | Med | 0.42 | 6.5 | 0.00 | May 13, 2026 | Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final. | |
| CVE-2026-42580 | Med | 0.42 | 6.5 | 0.00 | May 13, 2026 | Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's chunk size parser silently overflows int, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final. | |
| CVE-2026-40560 | Hig | 0.42 | 7.5 | 0.00 | Apr 29, 2026 | Starman versions before 0.4018 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Starman incorrectly prioritizes "Content-Length" over "Transfer-Encoding: chunked" when both headers are present in an HTTP request. Per RFC 7230 3.3.3, Transfer-Encoding must take precedence. An attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy. | |
| CVE-2026-24880 | Hig | 0.42 | 7.5 | 0.00 | Apr 9, 2026 | Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Apache Tomcat via invalid chunk extension. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.18, from 10.1.0-M1 through 10.1.52, from 9.0.0.M1 through 9.0.115, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other, unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.20, 10.1.52 or 9.0.116, which fix the issue. | |
| CVE-2025-23167 | Med | 0.42 | 6.5 | 0.00 | May 19, 2025 | A flaw in Node.js 20's HTTP parser allows improper termination of HTTP/1 headers using `\r\n\rX` instead of the required `\r\n\r\n`. This inconsistency enables request smuggling, allowing attackers to bypass proxy-based access controls and submit unauthorized requests. The issue was resolved by upgrading `llhttp` to version 9, which enforces correct header termination. Impact: * This vulnerability affects only Node.js 20.x users prior to the `llhttp` v9 upgrade. | |
| CVE-2025-31137 | Hig | 0.42 | 7.5 | 0.00 | Apr 1, 2025 | React Router is a multi-strategy router for React bridging the gap from React 18 to React 19. There is a vulnerability in Remix/React Router that affects all Remix 2 and React Router 7 consumers using the Express adapter. Basically, this vulnerability allows anyone to spoof the URL used in an incoming Request by putting a URL pathname in the port section of a URL that is part of a Host or X-Forwarded-Host header sent to a Remix/React Router request handler. This issue has been patched and released in Remix 2.16.3 and React Router 7.4.1. | |
| CVE-2023-4639 | Hig | 0.42 | 7.4 | 0.07 | Nov 17, 2024 | A flaw was found in Undertow, which incorrectly parses cookies with certain value-delimiting characters in incoming requests. This issue could allow an attacker to construct a cookie value to exfiltrate HttpOnly cookie values or spoof arbitrary additional cookie values, leading to unauthorized data access or modification. The main threat from this flaw impacts data confidentiality and integrity. |