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of outdated or incompatible HTTP protocol versions in the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
170 results · Clear filters · Feed
-
Medium 5.2
An inconsistent interpretation of http requests ('http request smuggling') vulnerability in Fortinet FortiOS 7.6.0, For…
-
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…
-
Medium 5.3
Libsoup: soupserver: denial of service via http request smuggling
A flaw was found in SoupServer. This HTTP request smuggling vulnerability occurs because SoupServer improperly handles requests that combine Transfer-Encoding: chunked and Connection: keep-alive headers. A remote, unauthenticated client can exploit this by se…
-
Medium 6.9
HTTP Request/Response Smuggling in Altitude Communication Server
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 betw…
-
Medium 6.9
Eclipse Vert.x Web static handler file access denial
The Vert.x Web static handler component cache can be manipulated to deny the access to static files served by the handler using specifically crafted request URI. The issue comes from an improper implementation of the C. rule of section 5.2.4 of RFC3986 and is…
-
Medium 6.3
AIOHTTP's Unicode processing of header values could cause parsing discrepancies
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 AIOHTTP is installe…
-
Medium 6.3
HTTP Request Smuggling in Quest Coexistence Manager for Notes
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Quest Coexistence Manager for Notes (Free/Busy Connector modules) allows HTTP Request Smuggling via the Content-Length-Transfer-Encoding (CL.TE) attack vector. T…
-
Medium 6.9
Member Login Script 3.3 Client-Side Request Desynchronization Vulnerability
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 …
-
Medium 4.8
Akamai Ghost on Akamai CDN edge servers before 2025-11-17 has a chunked request body processing error that can result i…
-
Medium 6.9
HTTP Header Smuggling via Trailer Merge
lighttpd1.4.80 incorrectly merged trailer fields into headers after http request parsing. This behavior can be exploited to conduct HTTP Header Smuggling attacks. Successful exploitation may allow an attacker to: * Bypass access control rules * Inject unsafe …
-
Medium 6.9
HTTP Desynchronisation in Vertex AI for certain third-party models
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.
-
Medium 6.3
Http4s vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section
Http4s is a Scala interface for HTTP services. In versions from 1.0.0-M1 to before 1.0.0-M45 and before 0.23.31, http4s is vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section. This vulnerability could enable attackers to bypa…
-
Medium 6.9
WatchGuard Firebox Authentication Portal Request Smuggling Vulnerability
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. WatchGuard does not believe…
-
Medium 6.3
Eventlet affected by HTTP request smuggling in unparsed trailers
Eventlet is a concurrent networking library for Python. Prior to version 0.40.3, the Eventlet WSGI parser is vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer sections. This vulnerability could enable attackers to, bypass front-end…
-
Medium 4.0
Akamai Ghost before 2025-07-21 allows HTTP Request Smuggling via an OPTIONS request that has an entity body, because th…
-
Medium —
mitmproxy binaries embed a vulnerable python-hyper/h2 dependency
mitmproxy 12.1.1 and below embed python-hyper/h2 ≤ v4.2.0, which has a gap in its HTTP/2 header validation. This enables request smuggling attacks when mitmproxy is in a configuration where it translates HTTP/2 to HTTP/1. For example, this affects reverse pro…
-
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…
-
Medium 4.5
EspoCRM is vulnerable to access denial through double slash in URI corrupting router cache
EspoCRM is a web application with a frontend designed as a single-page application and a REST API backend written in PHP. In versions 9.1.6 and below, if a user loads Espo in the browser with double slashes (e.g https://domain//#Admin) and the webserver does …
-
Medium 6.5
Ruby WEBrick read_header HTTP Request Smuggling Vulnerability
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 behind an HTTP proxy…
-
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…
-
Medium 5.4
Varnish Cache before 7.6.3 and 7.7 before 7.7.1, and Varnish Enterprise before 6.0.13r14, allow client-side desync via …
-
Medium 5.9
Query smuggling in ch-go library
When using the ch-go library, under a specific condition when the query includes a large, uncompressed malicious external data, it is possible for an attacker in control of such data to smuggle another query packet into the connection stream.
-
Medium 4.7
IBM Cognos Controller HTTP response smuggling
IBM Cognos Controller 11.0.0 through 11.1.0 is vulnerable to a Client-Side Desync (CSD) attack where an attacker could exploit a desynchronized browser connection that could lead to further cross-site scripting (XSS) attacks.
-
Medium 5.4
Varnish Cache before 7.6.2 and Varnish Enterprise before 6.0.13r10 allow client-side desync via HTTP/1 requests.
-
Medium 5.3
-
Medium 6.8
In Perfex Crm < 3.2.1, an authenticated attacker can send a crafted HTTP POST request to the affected upload_sales_file…
-
Medium 5.3
Inconsistent interpretation of HTTP requests ('HTTP Request/Response Smuggling') issue exists in HAProxy. If this vulne…
-
Medium 4.7
Org.keycloak/keycloak-quarkus-server: keycloak proxy header handling denial-of-service (dos) vulnerability
A vulnerability was found in the Keycloak Server. The Keycloak Server is vulnerable to a denial of service (DoS) attack due to improper handling of proxy headers. When Keycloak is configured to accept incoming proxy headers, it may accept non-IP values, such …
-
Medium 6.3
aiohttp vulnerable to request smuggling due to incorrect parsing of chunk extensions
aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.10.11, the Python parser parses newlines in chunk extensions incorrectly which can lead to request smuggling vulnerabilities under certain conditions. If a pure…
-
Medium 5.3
Vulnerability in the Oracle Banking Liquidity Management product of Oracle Financial Services Applications (component: …
-
Medium 5.3
Resteasy-netty4-cdi: resteasy-netty4: resteasy-reactor-netty: http request smuggling leading to client timeouts in resteasy-netty4
A vulnerability was found in the resteasy-netty4 library arising from improper handling of HTTP requests using smuggling techniques. When an HTTP smuggling request with an ASCII control character is sent, it causes the Netty HttpObjectDecoder to transition in…
-
Medium 5.9
In Mastodon 4.1.6, API endpoint rate limiting can be bypassed by setting a crafted HTTP request header.
-
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…
-
Medium 4.3
Loway - CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Loway - CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
-
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…
-
Medium 6.3
mhuertos phpLDAPadmin ajax_functions.js makeHttpRequest request smuggling
A vulnerability classified as critical was found in mhuertos phpLDAPadmin up to 665dbc2690ebeb5392d38f1fece0a654225a0b38. Affected by this vulnerability is the function makeHttpRequest of the file htdocs/js/ajax_functions.js. The manipulation leads to http re…
-
Medium 5.9
GoRouter Denial of Service Attack
Improper handling of requests in Routing Release > v0.273.0 and <= v0.297.0 allows an unauthenticated attacker to degrade the service availability of the Cloud Foundry deployment if performed at scale.
-
Medium 6.5
The team has identified a critical vulnerability in the http server of the most recent version of Node, where malformed…
-
Medium 6.3
Apache APISIX: Forward-Auth Request Smuggling
Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in Apache APISIX when using `forward-auth` plugin.This issue affects Apache APISIX: from 3.8.0, 3.9.0. Users are recommended to upgrade to version 3.8.1, 3.9.1 or higher, wh…
-
Medium 6.3
Apache HTTP Server: HTTP Response Splitting in multiple modules
HTTP Response splitting in multiple modules in Apache HTTP Server allows an attacker that can inject malicious response headers into backend applications to cause an HTTP desynchronization attack. Users are recommended to upgrade to version 2.4.59, which fixe…