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Weakness (CWE)

CWE-444: Inconsistent Interpretation of HTTP Requests

Base Incomplete

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of outdated or incompatible HTTP protocol versions in the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)
  1. Implementation

    Use a web server that employs a strict HTTP parsing procedure, such as Apache [REF-433].

  2. Implementation

    Use only SSL communication.

  3. Implementation

    Terminate the client session after each request.

  4. System Configuration

    Turn all pages to non-cacheable.

Source: MITRE CWE-444

11 results · Clear filters · Feed

  • Critical 9.3
    CVE-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…

  • Critical 9.1
    CVE-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…

  • Critical 9.3
    CVE-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…

  • Critical 9.9
    CVE-2025-55315 Public exploit EPSS 67%

    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.

  • Critical 10.0
    CVE-2024-41110 Public exploit EPSS 16%

    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…

  • Critical 9.6
    CVE-2023-41265 Exploited · Ransomware Public exploit EPSS 88%

    An HTTP Request Tunneling vulnerability found in Qlik Sense Enterprise for Windows for versions May 2023 Patch 3 and ea…

    KEV Dec 7, 2023
  • Critical 9.8
    CVE-2023-25690 Public exploit EPSS 84%

    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…

  • Critical 9.1
    CVE-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…

  • Critical 9.8
    CVE-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.

  • Critical 9.8
    CVE-2022-22536 Exploited Public exploit EPSS 98%

    SAP NetWeaver Application Server ABAP, SAP NetWeaver Application Server Java, ABAP Platform, SAP Content Server 7.53 an…

    KEV Aug 18, 2022
  • Critical 9.8
    CVE-2021-30180 Public exploit EPSS 60%

    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…