CWE-444
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
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 (429)
page 6 of 22| CVE | Vendor / Product | Sev | Risk | CVSS | EPSS | KEV | Published | Description |
|---|---|---|---|---|---|---|---|---|
| CVE-2026-69205 | Hig | 0.50 | 8.7 | 0.00 | Sep 15, 2026 | Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HeaderP.parse uses a case-sensitive substring test for the Transfer-Encoding value and decodes header bytes with the platform default charset. Values such as Chunked are not recognized,… | ||
| CVE-2026-28369 | Hig | 0.50 | 8.7 | 0.01 | Mar 27, 2026 | A flaw was found in Undertow. When Undertow receives an HTTP request where the first header line starts with one or more spaces, it incorrectly processes the request by stripping these leading spaces. This behavior, which violates HTTP standards, can be exploited by a remote… | ||
| CVE-2026-28368 | Hig | 0.50 | 8.7 | 0.01 | Mar 27, 2026 | A flaw was found in Undertow. This vulnerability allows a remote attacker to construct specially crafted requests where header names are parsed differently by Undertow compared to upstream proxies. This discrepancy in header interpretation can be exploited to launch request… | ||
| CVE-2026-28367 | Hig | 0.50 | 8.7 | 0.01 | Mar 27, 2026 | A flaw was found in Undertow. A remote attacker can exploit this vulnerability by sending `\r\r\r` as a header block terminator. This can be used for request smuggling with certain proxy servers, such as older versions of Apache Traffic Server and Google Cloud Classic… | ||
| CVE-2024-33452 | Hig | 0.50 | 7.7 | 0.01 | Apr 22, 2025 | An issue in OpenResty lua-nginx-module v.0.10.26 and before allows a remote attacker to conduct HTTP request smuggling via a crafted HEAD request. | ||
| CVE-2022-26377 | Hig | 0.50 | 7.5 | 0.21 | Jun 9, 2022 | 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 Server 2.4 version… | ||
| CVE-2026-74848 | Hig | 0.49 | 7.5 | 0.01 | Aug 27, 2026 | Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Apache APISIX. An attacker could make other clients receive attacker-chosen or other users' responses on serverless-plugin routes. This issue affects Apache APISIX: from 2.12.0… | ||
| CVE-2026-65370 | Hig | 0.49 | 7.5 | 0.00 | Aug 12, 2026 | ServiceTalk HTTP/1.x incorrectly handles malformed Transfer-Encoding which could result in request smuggling attacks. This vulnerability is addressed in servicetalk version 0.42.65. | ||
| CVE-2026-59898 | Hig | 0.49 | 7.5 | 0.00 | Jul 29, 2026 | Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, ab attacker can force WebSocket upgrade via the lax V07 (or V08) handshaker by sending `Sec-WebSocket-Version: 7` and omitting `Connection: Upgrade` /… | ||
| CVE-2026-67182 | Hig | 0.49 | 7.5 | 0.01 | Jul 28, 2026 | 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 connections without… | ||
| CVE-2025-3110 | Hig | 0.49 | 7.5 | 0.00 | Jul 8, 2026 | OpenVPN Access Server 2.7.2 through 3.1.0 accepts bare line-feed sequences inside HTTP header values, allowing remote attackers to perform HTTP request smuggling when deployed behind a reverse proxy | ||
| CVE-2026-8620 | Hig | 0.49 | 7.5 | 0.00 | May 26, 2026 | IBM Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty 8.5, 9.0 IBM WebSphere Application Server and WebSphere Application Server Liberty are vulnerable to HTTP request smuggling in the Web Server Plug-ins through a specially crafted request. | ||
| CVE-2026-40562 | Hig | 0.49 | 7.5 | 0.01 | May 6, 2026 | Gazelle versions through 0.49 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Gazelle 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… | ||
| CVE-2026-33805 | Hig | 0.49 | 8.6 | 0.01 | Apr 15, 2026 | @fastify/reply-from v12.6.1 and earlier and @fastify/http-proxy v11.4.3 and earlier process the client's Connection header after the proxy has added its own headers via rewriteRequestHeaders. This allows attackers to retroactively strip proxy-added headers from upstream requests… | ||
| CVE-2026-31842 | Hig | 0.49 | 7.5 | 0.01 | Apr 7, 2026 | Tinyproxy through 1.11.3 is vulnerable to HTTP request parsing desynchronization due to a case-sensitive comparison of the Transfer-Encoding header in src/reqs.c. The is_chunked_transfer function uses strcmp to compare the header value against "chunked", even though RFC 7230… | ||
| CVE-2025-61258 | Hig | 0.49 | 7.5 | 0.01 | Dec 9, 2025 | Outsystems Platform Server 11.18.1.37828 allows attackers to cause a denial of service via a crafted content-length value mismatching the body length. NOTE: the Supplier indicates that they are unable to reproduce this. | ||
| CVE-2025-4600 | Hig | 0.49 | 7.5 | 0.00 | May 16, 2025 | A request smuggling vulnerability existed in the Google Cloud Classic Application Load Balancer due to improper handling of chunked-encoded HTTP requests. This allowed attackers to craft requests that could be misinterpreted by backend servers. The issue was fixed by disallowing… | ||
| CVE-2024-52530 | Hig | 0.49 | 7.5 | 0.01 | Nov 11, 2024 | GNOME libsoup before 3.6.0 allows HTTP request smuggling in some configurations because '\0' characters at the end of header names are ignored, i.e., a "Transfer-Encoding\0: chunked" header is treated the same as a "Transfer-Encoding: chunked" header. | ||
| 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-2024-8912 | Hig | 0.49 | 7.5 | 0.00 | Oct 11, 2024 | An HTTP Request Smuggling vulnerability in Looker allowed an unauthorized attacker to capture HTTP responses destined for legitimate users. There are two Looker versions that are hosted by Looker: * Looker (Google Cloud core) was found to be vulnerable. This issue has… |
- risk 0.50cvss 8.7epss 0.00
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HeaderP.parse uses a case-sensitive substring test for the Transfer-Encoding value and decodes header bytes with the platform default charset. Values such as Chunked are not recognized,…
- risk 0.50cvss 8.7epss 0.01
A flaw was found in Undertow. When Undertow receives an HTTP request where the first header line starts with one or more spaces, it incorrectly processes the request by stripping these leading spaces. This behavior, which violates HTTP standards, can be exploited by a remote…
- risk 0.50cvss 8.7epss 0.01
A flaw was found in Undertow. This vulnerability allows a remote attacker to construct specially crafted requests where header names are parsed differently by Undertow compared to upstream proxies. This discrepancy in header interpretation can be exploited to launch request…
- risk 0.50cvss 8.7epss 0.01
A flaw was found in Undertow. A remote attacker can exploit this vulnerability by sending `\r\r\r` as a header block terminator. This can be used for request smuggling with certain proxy servers, such as older versions of Apache Traffic Server and Google Cloud Classic…
- risk 0.50cvss 7.7epss 0.01
An issue in OpenResty lua-nginx-module v.0.10.26 and before allows a remote attacker to conduct HTTP request smuggling via a crafted HEAD request.
- risk 0.50cvss 7.5epss 0.21
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 Server 2.4 version…
- risk 0.49cvss 7.5epss 0.01
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Apache APISIX. An attacker could make other clients receive attacker-chosen or other users' responses on serverless-plugin routes. This issue affects Apache APISIX: from 2.12.0…
- risk 0.49cvss 7.5epss 0.00
ServiceTalk HTTP/1.x incorrectly handles malformed Transfer-Encoding which could result in request smuggling attacks. This vulnerability is addressed in servicetalk version 0.42.65.
- risk 0.49cvss 7.5epss 0.00
Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, ab attacker can force WebSocket upgrade via the lax V07 (or V08) handshaker by sending `Sec-WebSocket-Version: 7` and omitting `Connection: Upgrade` /…
- risk 0.49cvss 7.5epss 0.01
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 connections without…
- risk 0.49cvss 7.5epss 0.00
OpenVPN Access Server 2.7.2 through 3.1.0 accepts bare line-feed sequences inside HTTP header values, allowing remote attackers to perform HTTP request smuggling when deployed behind a reverse proxy
- risk 0.49cvss 7.5epss 0.00
IBM Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty 8.5, 9.0 IBM WebSphere Application Server and WebSphere Application Server Liberty are vulnerable to HTTP request smuggling in the Web Server Plug-ins through a specially crafted request.
- risk 0.49cvss 7.5epss 0.01
Gazelle versions through 0.49 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Gazelle 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…
- risk 0.49cvss 8.6epss 0.01
@fastify/reply-from v12.6.1 and earlier and @fastify/http-proxy v11.4.3 and earlier process the client's Connection header after the proxy has added its own headers via rewriteRequestHeaders. This allows attackers to retroactively strip proxy-added headers from upstream requests…
- risk 0.49cvss 7.5epss 0.01
Tinyproxy through 1.11.3 is vulnerable to HTTP request parsing desynchronization due to a case-sensitive comparison of the Transfer-Encoding header in src/reqs.c. The is_chunked_transfer function uses strcmp to compare the header value against "chunked", even though RFC 7230…
- risk 0.49cvss 7.5epss 0.01
Outsystems Platform Server 11.18.1.37828 allows attackers to cause a denial of service via a crafted content-length value mismatching the body length. NOTE: the Supplier indicates that they are unable to reproduce this.
- risk 0.49cvss 7.5epss 0.00
A request smuggling vulnerability existed in the Google Cloud Classic Application Load Balancer due to improper handling of chunked-encoded HTTP requests. This allowed attackers to craft requests that could be misinterpreted by backend servers. The issue was fixed by disallowing…
- risk 0.49cvss 7.5epss 0.01
GNOME libsoup before 3.6.0 allows HTTP request smuggling in some configurations because '\0' characters at the end of header names are ignored, i.e., a "Transfer-Encoding\0: chunked" header is treated the same as a "Transfer-Encoding: chunked" header.
- risk 0.49cvss 7.5epss 0.01
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.
- risk 0.49cvss 7.5epss 0.00
An HTTP Request Smuggling vulnerability in Looker allowed an unauthorized attacker to capture HTTP responses destined for legitimate users. There are two Looker versions that are hosted by Looker: * Looker (Google Cloud core) was found to be vulnerable. This issue has…