Weakness (CWE)
CWE-444: Inconsistent Interpretation of HTTP Requests
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.
More detail
HTTP requests or responses ("messages") can be
malformed or unexpected in ways that cause web servers or
clients to interpret the messages in different ways than
intermediary HTTP agents such as load balancers, reverse
proxies, web caching proxies, application firewalls,
etc. For example, an adversary may be able to add duplicate
or different header fields that a client or server might
interpret as one set of messages, whereas the intermediary
might interpret the same sequence of bytes as a different
set of messages. For example, discrepancies can arise in
how to handle duplicate headers like two Transfer-encoding
(TE) or two Content-length (CL), or the malicious HTTP
message will have different headers for TE and
CL.
The inconsistent parsing and interpretation of messages
can allow the adversary to "smuggle" a message to the
client/server without the intermediary being aware of it.
This weakness is usually the result of the usage
of outdated or incompatible HTTP protocol versions in the
HTTP agents.
How to prevent it (4 mitigations)
-
Implementation
Use a web server that employs a strict HTTP parsing procedure, such as Apache [REF-433].
-
Implementation
Use only SSL communication.
-
Implementation
Terminate the client session after each request.
-
System Configuration
Turn all pages to non-cacheable.
Source: MITRE CWE-444
43 results · Clear filters · Feed
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Critical 9.3CVE-2026-88773 Public exploit
HTTP Request Smuggling
Inconsistent interpretation of HTTP requests ('HTTP Request/Response smuggling') vulnerability in Citrix NetScaler ADC and Citrix NetScaler Gateway. This issue affects ADC: before 14.1-73.37, before 13.1-64.23, before 14.1-73.37 FIPS, and before 13.1-37.279 a…
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Critical 9.1CVE-2026-86350 Public exploit
Apache Tomcat: Regression in fix for CVE-2026-41293 can trigger request header mix-up
Inconsistent interpretation of HTTP/2 requests ('HTTP Request/Response smuggling') vulnerability in Apache Tomcat caused by a regression in fix for CVE-2026-41293 can trigger request header mix-up. This issue affects Apache Tomcat: from 11.0.22 through 11.0.2…
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High 8.8CVE-2026-88009 Public exploit
Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging
Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.57, and 3.7.13, Traefik accepts a rootless HTTP/1 request target that Go stores in URL.Opaque while leaving URL.Path empty. The rewriteRequestBuilder path evaluates routing, path sa…
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High 7.0CVE-2026-88008 Public exploit
Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization
Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared backend. If the backend acce…
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Medium 5.6CVE-2026-84380 Public exploit
HTTPX2: Conflicting Content-Length and Transfer-Encoding headers can be auto-generated
HTTPX2 is a next generation HTTP client for Python. Prior to 2.11.0, Request._prepare() in src/httpx2/httpx2/_models.py can add a body-derived Content-Length header to a request that already contains a caller-supplied Transfer-Encoding header because its setd…
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Medium 6.5CVE-2026-51376 Public exploit
An issue in BitChat for iOS v1.15.0 allows a remote attacker to cause a denial of service via an unauthenticated MESSAG…
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Medium 5.3CVE-2026-71554 Public exploit
h2: Duplicate Host header could facilitate request smuggling
h2 is a pure-Python implementation of a HTTP/2 protocol stack. Versions up to and including 4.4.0 accept request header blocks containing more than one Host header, and forward every Host header to the consuming application. Where the consumer downgrades HTTP…
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Low 3.7CVE-2026-58044 Public exploit
A flaw in Node.js HTTP client can cause a request desynchronization for Node.js-based forwarding proxies that rebuild o…
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Medium 6.3CVE-2026-69243 Public exploit
AIOHTTP: HTTP request smuggling via WebSocket upgrade
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.2, the HTTP parsers were vulnerable to a request smuggling attack relating to WebSocket upgrades. If using the server-side component, an attacker may be able to exec…
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High 7.5CVE-2026-67182 Public exploit
Rouille 0.3.3 - 3.6.2 HTTP Request Smuggling via proxy Header Injection
Rouille 0.3.3 through 3.6.2 contains an HTTP request smuggling vulnerability that allows remote attackers to bypass access controls by injecting bare line feed characters (0x0A) into client-supplied request header values that are copied verbatim to upstream c…
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Medium 5.4CVE-2026-67181 Public exploit
Rouille 0.3.3 - 3.6.2 HTTP Request Smuggling via proxy Transfer-Encoding Header
Rouille 0.3.3 through 3.6.2 contains an HTTP request smuggling vulnerability that allows remote attackers to desynchronize HTTP message boundaries by exploiting improper header forwarding in the proxy implementation. The proxy in src/proxy.rs forwards the cli…
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Medium 5.4CVE-2026-66752 Public exploit
tiny-http 0.12.0 HTTP Request Smuggling via Transfer-Encoding Handling
tiny-http through 0.12.0 contains an HTTP request smuggling vulnerability that allows remote attackers to desynchronize request framing by sending a Transfer-Encoding header with any value, including non-chunked codings, which causes the library to unconditio…
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Medium 6.5
Starlette has missing Host header validation that poisons request.url.path, bypassing path-based security checks
Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP `Host` request header was not validated before being used to reconstruct `request.url`. Because the routing algorithm relies on the raw HTTP path while `request.url` is rebuil…
KEV Sep 2, 2026 -
High 7.4CVE-2026-2332 Public exploit
HTTP Request Smuggling via Chunked Extension Quoted-String Parsing
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.htm…
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Medium 4.8CVE-2026-40175 Public exploit
Axios has Unrestricted Cloud Metadata Exfiltration via Header Injection Chain
Axios is a promise based HTTP client for the browser and Node.js. Versions prior to 1.15.0 and 0.3.1 are vulnerable to a specific gadget-style attack chain in which prototype pollution in a third-party dependency may be leveraged to inject unsanitized header …
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High 7.5CVE-2026-24880 Public exploit
Apache Tomcat: Request smuggling via invalid chunk extension
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 throug…
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Medium 6.3CVE-2026-29057 Public exploit
Next.js: HTTP request smuggling in rewrites
Next.js is a React framework for building full-stack web applications. Starting in version 9.5.0 and prior to versions 15.5.13 and 16.1.7, when Next.js rewrites proxy traffic to an external backend, a crafted `DELETE`/`OPTIONS` request using `Transfer-Encodin…
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Critical 9.3CVE-2026-2835 Public exploit
HTTP Request Smuggling via HTTP/1.0 and Transfer-Encoding Misparsing
An HTTP Request Smuggling vulnerability (CWE-444) has been found in Pingora's parsing of HTTP/1.0 and Transfer-Encoding requests. The issue occurs due to improperly allowing HTTP/1.0 request bodies to be close-delimited and incorrect handling of multiple Tran…
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Medium 5.3CVE-2026-1801 Public exploit
Libsoup: libsoup: http request smuggling via malformed chunk headers
A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup accepts malformed chunk headers, such as lone line fee…
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Critical 9.9
ASP.NET Security Feature Bypass Vulnerability
Inconsistent interpretation of http requests ('http request/response smuggling') in ASP.NET Core allows an authorized attacker to bypass a security feature over a network.
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High 7.5
Vulnerability in the Oracle Configurator product of Oracle E-Business Suite (component: Runtime UI). Supported versions…
KEV Oct 20, 2025 -
Medium 4.0CVE-2025-32094 Public exploit
An issue was discovered in Akamai Ghost, as used for the Akamai CDN platform before 2025-03-26. Under certain circumsta…
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Medium 6.5CVE-2025-23167 Public exploit
A flaw in Node.js 20's HTTP parser allows improper termination of HTTP/1 headers using `\r\n\rX` instead of the require…
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High 7.5CVE-2025-31137 Public exploit
Remix and React Router allow URL manipulation via Host / X-Forwarded-Host headers
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 …
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Medium 5.4CVE-2024-45614 Public exploit
Header normalization allows for client to clobber proxy set headers in Puma
Puma is a Ruby/Rack web server built for parallelism. In affected versions clients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing a underscore version of the same header (X-Forwarded_For). Any users relying on proxy se…
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Medium 5.3CVE-2024-35538 Public exploit
Typecho v1.3.0 was discovered to contain a Client IP Spoofing vulnerability, which allows attackers to falsify their IP…
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Critical 10.0
Moby authz zero length regression
Moby is an open-source project created by Docker for software containerization. A security vulnerability has been detected in certain versions of Docker Engine, which could allow an attacker to bypass authorization plugins (AuthZ) under specific circumstances…
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Critical 9.6
An HTTP Request Tunneling vulnerability found in Qlik Sense Enterprise for Windows for versions May 2023 Patch 3 and ea…
KEV Dec 7, 2023 -
High 7.3CVE-2023-25950 Public exploit
HTTP request/response smuggling vulnerability in HAProxy version 2.7.0, and 2.6.1 to 2.6.7 allows a remote attacker to …
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Critical 9.8
Apache HTTP Server: HTTP request splitting with mod_rewrite and mod_proxy
Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggling attack. Configurations are affected when mod_proxy is enabled along with some form of RewriteRule or ProxyPassMatch in which a non-specific patter…
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Critical 9.1CVE-2023-25725 Public exploit
HAProxy before 2.7.3 may allow a bypass of access control because HTTP/1 headers are inadvertently lost in some situati…
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High 7.5CVE-2022-45059 Public exploit
An issue was discovered in Varnish Cache 7.x before 7.1.2 and 7.2.x before 7.2.1. A request smuggling attack can be per…
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Critical 9.8CVE-2022-2466 Public exploit
Quarkus does not terminate HTTP requests header context
It was found that Quarkus 2.10.x does not terminate HTTP requests header context which may lead to unpredictable behavior.
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Unscored —
mod_proxy_ajp: Possible request smuggling
Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in mod_proxy_ajp of Apache HTTP Server allows an attacker to smuggle requests to the AJP server it forwards requests to. This issue affects Apache HTTP Server Apache HTTP Se…
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Unscored —
HTTP request smuggling vulnerability in Apache HTTP Server 2.4.52 and earlier
Apache HTTP Server 2.4.52 and earlier fails to close inbound connection when errors are encountered discarding the request body, exposing the server to HTTP Request Smuggling
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Critical 9.8
SAP NetWeaver Application Server ABAP, SAP NetWeaver Application Server Java, ABAP Platform, SAP Content Server 7.53 an…
KEV Aug 18, 2022 -
High 8.1CVE-2021-39214 Public exploit
Lacking Protection against HTTP Request Smuggling in mitmproxy
mitmproxy is an interactive, SSL/TLS-capable intercepting proxy. In mitmproxy 7.0.2 and below, a malicious client or server is able to perform HTTP request smuggling attacks through mitmproxy. This means that a malicious client/server could smuggle a request/…
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Critical 9.8
Apache Dubbo RCE on customers via Condition route poisoning (Unsafe YAML unmarshaling)
Apache Dubbo prior to 2.7.9 support Tag routing which will enable a customer to route the request to the right server. These rules are used by the customers when making a request in order to find the right endpoint. When parsing these YAML rules, Dubbo custom…
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Unscored —
Node.js versions before 10.23.1, 12.20.1, 14.15.4, 15.5.1 allow two copies of a header field in an HTTP request (for ex…
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High 7.5CVE-2020-25613 Public exploit
WEBRick vulnerable to HTTP Request/Response Smuggling
An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1. WEBrick, a simple HTTP server bundled with Ruby, had not checked the transfer-encoding header value rigorously. An attacker may potentially exploit this issue to bypa…