CWE-444— Inconsistent Interpretation of HTTP Requests (HTTP Request Smuggling)
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.— MITRE CWE catalog
484 active CVEs classified under this weakness category. Sourced from NVD, GHSA, and vendor advisories. Full definition on MITRE →
CVEs classified under CWE-444page 7 of 10
- CVE-2026-15396MEDIUMCVSS 6.5EG 6.52026-09-14
IBM WebSphere Application Server 8.5 and 9.0, and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.8 are vulnerable to HTTP request smuggling, caused by improper parsing of the HTTP transfer-encoding request header. By …
- CVE-2026-15634MEDIUMCVSS 6.5EG 6.52026-09-14
IBM WebSphere Application Server 8.5 and 9.0, and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.8 are vulnerable to HTTP request smuggling, caused by improper parsing of the HTTP transfer-encoding request header. By …
- CVE-2026-89044MEDIUMCVSS 6.5EG 6.52026-09-10
Netty versions 4.1.133.Final through 4.1.137.Final and 4.2.13.Final through 4.2.17.Final fail to properly validate the final transfer coding in the Transfer-Encoding header, allowing attackers to smuggle requests by using malformed encodin…
- CVE-2026-51376MEDIUMCVSS 6.5EG 6.52026-08-28
An issue in BitChat for iOS v1.15.0 allows a remote attacker to cause a denial of service via an unauthenticated MESSAGE packet into the mesh gossip cache
- CVE-2026-16728MEDIUMCVSS 6.5EG 6.52026-07-29
undici's retry interceptor can deliver a response whose body length does not match the Content-Length header exposed to the application after a retry or resume of a partial response. In undici before 6.28.0, from 7.0.0 up to before 7.29.0,…
- CVE-2025-71381MEDIUMCVSS 6.5EG 6.52026-06-30
Hono before 4.10.3 contains a flaw in its CORS middleware: when the origin is not set to "*", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by th…
- CVE-2026-42580MEDIUMCVSS 6.5EG 6.52026-05-13
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.Fina…
- CVE-2026-34441MEDIUMCVSS 6.5EG 6.52026-03-31
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.40.0, cpp-httplib is vulnerable to HTTP Request Smuggling. The server's static file handler serves GET responses without consuming the req…
- CVE-2026-29057MEDIUMCVSS 6.5EG 6.52026-03-18
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 usi…
- CVE-2026-32240MEDIUMCVSS 6.5EG 6.52026-03-12
Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. In theory, t…
- CVE-2026-32239MEDIUMCVSS 6.5EG 6.52026-03-12
Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, a negative Content-Length value was converted to unsigned, treating it as an impossibly large length instead. In theory, this bug could enable HTTP r…
- CVE-2026-1801MEDIUMCVSS 6.5EG 6.52026-02-03
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, s…
- CVE-2025-69224MEDIUMCVSS 6.5EG 6.52026-01-05
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Versions 3.13.2 and below of the Python HTTP parser may allow a request smuggling attack with the presence of non-ASCII characters. If a pure Python version of…
- CVE-2025-23167MEDIUMCVSS 6.5EG 6.52025-05-19
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…
- CVE-2024-27982MEDIUMCVSS 6.5EG 6.52024-05-07
The team has identified a critical vulnerability in the http server of the most recent version of Node, where malformed headers can lead to HTTP request smuggling. Specifically, if a space is placed before a content-length header, it is no…
- CVE-2023-50811MEDIUMCVSS 6.5EG 6.52024-03-19
An issue discovered in SELESTA Visual Access Manager 4.38.6 allows attackers to modify the “computer” POST parameter related to the ID of a specific reception by POST HTTP request interception. Iterating that parameter, it has been pos…
- CVE-2024-27439MEDIUMCVSS 6.5EG 6.52024-03-19
An error in the evaluation of the fetch metadata headers could allow a bypass of the CSRF protection in Apache Wicket. This issue affects Apache Wicket: from 9.1.0 through 9.16.0, and the milestone releases for the 10.0 series. Apache Wick…
- CVE-2024-23829MEDIUMCVSS 6.5EG 6.52024-01-29
aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Security-sensitive parts of the Python HTTP parser retained minor differences in allowable character sets, that must trigger error handling to robustly match f…
- CVE-2023-47641MEDIUMCVSS 6.5EG 6.52023-11-14
aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Affected versions of aiohttp have a security vulnerability regarding the inconsistent interpretation of the http protocol. HTTP/1.1 is a persistent protocol, i…
- CVE-2022-1705MEDIUMCVSS 6.5EG 6.52022-08-10
Acceptance of some invalid Transfer-Encoding headers in the HTTP/1 client in net/http before Go 1.17.12 and Go 1.18.4 allows HTTP request smuggling if combined with an intermediate server that also improperly fails to reject the header as …
- CVE-2021-43797MEDIUMCVSS 6.5EG 6.52021-12-09
Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. Netty prior to version 4.1.71.Final skips control chars when they are present at the beg…
- CVE-2021-41267MEDIUMCVSS 6.5EG 6.52021-11-24
Symfony/Http-Kernel is the HTTP kernel component for Symfony, a PHP framework for web and console applications and a set of reusable PHP components. Headers that are not part of the "trusted_headers" allowed list are ignored and protect us…
- CVE-2021-22959MEDIUMCVSS 6.5EG 6.52021-11-15
The parser in accepts requests with a space (SP) right after the header name before the colon. This can lead to HTTP Request Smuggling (HRS) in llhttp < v2.1.4 and < v6.0.6.
- CVE-2021-22960MEDIUMCVSS 6.5EG 6.52021-11-03
The parse function in llhttp < 2.1.4 and < 6.0.6. ignores chunk extensions when parsing the body of chunked requests. This leads to HTTP Request Smuggling (HRS) under certain conditions.
- CVE-2021-36740MEDIUMCVSS 6.5EG 6.52021-07-14
Varnish Cache, with HTTP/2 enabled, allows request smuggling and VCL authorization bypass via a large Content-Length header for a POST request. This affects Varnish Enterprise 6.0.x before 6.0.8r3, and Varnish Cache 5.x and 6.x before 6.5.…
- CVE-2020-4896MEDIUMCVSS 6.5EG 6.52021-01-07
IBM Emptoris Sourcing 10.1.0, 10.1.1, and 10.1.3 is vulnerable to web cache poisoning, caused by improper input validation by modifying HTTP request headers. IBM X-Force ID: 190987.
- CVE-2020-8287MEDIUMCVSS 6.5EG 6.52021-01-06
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 example, two Transfer-Encoding header fields). In this case, Node.js identifies the first header field and ignores the sec…
- CVE-2020-35884MEDIUMCVSS 6.5EG 6.52020-12-31
An issue was discovered in the tiny_http crate through 2020-06-16 for Rust. HTTP Request smuggling can occur via a malformed Transfer-Encoding header.
- CVE-2020-26129MEDIUMCVSS 6.5EG 6.52020-11-16
In JetBrains Ktor before 1.4.1, HTTP request smuggling was possible.
- CVE-2020-15810MEDIUMCVSS 6.5EG 6.52020-09-02
An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Smuggling attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, includin…
- CVE-2020-10719MEDIUMCVSS 6.5EG 6.52020-05-26
A flaw was found in Undertow in versions before 2.1.1.Final, regarding the processing of invalid HTTP requests with large chunk sizes. This flaw allows an attacker to take advantage of HTTP request smuggling.
- CVE-2019-15272MEDIUMCVSS 6.5EG 6.52019-10-02
A vulnerability in the web-based interface of Cisco Unified Communications Manager and Cisco Unified Communications Manager Session Management Edition (SME) could allow an unauthenticated, remote attacker to bypass security restrictions. T…
- CVE-2018-8004MEDIUMCVSS 6.5EG 6.52018-08-29
There are multiple HTTP smuggling and cache poisoning issues when clients making malicious requests interact with Apache Traffic Server (ATS). This affects versions 6.0.0 to 6.2.2 and 7.0.0 to 7.1.3. To resolve this issue users running 6.x…
- CVE-2017-2666MEDIUMCVSS 6.5EG 6.52018-07-27
It was discovered in Undertow that the code that parsed the HTTP request line permitted invalid characters. This could be exploited, in conjunction with a proxy that also permitted the invalid characters but with a different interpretation…
- CVE-2025-6442MEDIUMCVSS 5.9EG 6.52025-06-25
Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed …
- CVE-2021-23336MEDIUMCVSS 5.9EG 6.52021-02-15
The package python/cpython from 0 and before 3.6.13, from 3.7.0 and before 3.7.10, from 3.8.0 and before 3.8.8, from 3.9.0 and before 3.9.2 are vulnerable to Web Cache Poisoning via urllib.parse.parse_qsl and urllib.parse.parse_qs by using…
- CVE-2022-33876MEDIUMCVSS 5.4EG 6.52022-12-06
Multiple instances of improper input validation vulnerability in Fortinet FortiADC version 7.1.0, version 7.0.0 through 7.0.2 and version 6.2.4 and below allows an authenticated attacker to retrieve files with specific extension from the u…
- CVE-2021-23339MEDIUMCVSS 5.0EG 6.52021-02-17
This affects all versions before 10.1.14 and from 10.2.0 to 10.2.4 of package com.typesafe.akka:akka-http-core. It allows multiple Transfer-Encoding headers.
- CVE-2022-21826MEDIUMCVSS 5.4EG 6.42022-09-30
Pulse Secure version 9.115 and below may be susceptible to client-side http request smuggling, When the application receives a POST request, it ignores the request's Content-Length header and leaves the POST body on the TCP/TLS socket. Thi…
- CVE-2026-114216MEDIUMCVSS 6.3EG 6.32026-10-26
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to smuggle a second request past a front-end pro…
- CVE-2026-105298MEDIUMCVSS 6.3EG 6.32026-10-20
Summary Before version 0.9.0, Pingora accepted HTTP/2 requests whose Host header differed from the :authority pseudo-header. Request filters, cache keys, and logs that read the request URI (session.req_header().uri) saw the :authority v…
- CVE-2026-111750MEDIUMCVSS 6.3EG 6.32026-10-19
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the pure Python parser accepts ambiguous HTTP request framing. An unauthenticated attacker can consequently smuggle requests when an applicati…
- CVE-2026-77802MEDIUMCVSS 6.3EG 6.32026-10-05
In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, HTTP request smuggling is possible in the proxy request forwarding component. Requests containing multiple Content-Length headers with conflicting v…
- CVE-2026-94194MEDIUMCVSS 6.3EG 6.32026-09-28
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in elixir-mint mint allows a malicious HTTP/1 server to desynchronize an intermediary and the Mint client on a pooled connection, poisoning the …
- CVE-2026-82672MEDIUMCVSS 6.3EG 6.32026-09-19
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in elixir-mint mint allows a malicious HTTP/1 server to desynchronize a strict intermediary and the Mint client on a pooled connection, enabling…
- CVE-2026-63379MEDIUMCVSS 6.3EG 6.32026-08-20
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent processes chunked HTTP trailers in http.c through evhttp_read_trailer and merges them into request headers. The fix introduces evhttp_parse_headers_impl_ …
- CVE-2026-73051MEDIUMCVSS 6.3EG 6.32026-08-14
actix-http versions before 3.12.1 contain an HTTP request smuggling vulnerability in the HTTP/1.1 parser that accepts requests with both Content-Length and Transfer-Encoding: chunked headers. Unauthenticated remote attackers can exploit th…
- CVE-2026-69243MEDIUMCVSS 6.3EG 6.32026-08-03
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…
- CVE-2026-59249MEDIUMCVSS 6.3EG 6.32026-07-16
Inconsistent interpretation of HTTP requests (HTTP response smuggling) vulnerability in elixir-mint mint allows a malicious HTTP/1 server to desynchronize a strict intermediary and the Mint client on the same pooled connection, enabling re…
- CVE-2026-49753MEDIUMCVSS 6.3EG 6.32026-06-02
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in elixir-mint Mint allows attacker-controlled HTTP/1 servers to desynchronise response framing on shared connections. Mint's HTTP/1 Content-Le…
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