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
487 active CVEs classified under this weakness category. Sourced from NVD, GHSA, and vendor advisories. Full definition on MITRE →
CVEs classified under CWE-444page 10 of 10
- CVE-2021-21299MEDIUMCVSS 4.8EG 4.82021-02-11
hyper is an open-source HTTP library for Rust (crates.io). In hyper from version 0.12.0 and before versions 0.13.10 and 0.14.3 there is a vulnerability that can enable a request smuggling attack. The HTTP server code had a flaw that incorr…
- CVE-2020-10687MEDIUMCVSS 4.8EG 4.82020-09-23
A flaw was discovered in all versions of Undertow before Undertow 2.2.0.Final, where HTTP request smuggling related to CVE-2017-2666 is possible against HTTP/1.x and HTTP/2 due to permitting invalid characters in an HTTP request. This flaw…
- CVE-2020-1935MEDIUMCVSS 4.8EG 4.82020-02-24
In Apache Tomcat 9.0.0.M1 to 9.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99 the HTTP header parsing code used an approach to end-of-line parsing that allowed some invalid HTTP headers to be parsed as valid. This led to a possibility of HTTP R…
- CVE-2019-17569MEDIUMCVSS 4.8EG 4.82020-02-24
The refactoring present in Apache Tomcat 9.0.28 to 9.0.30, 8.5.48 to 8.5.50 and 7.0.98 to 7.0.99 introduced a regression. The result of the regression was that invalid Transfer-Encoding headers were incorrectly processed leading to a possi…
- CVE-2022-39163MEDIUMCVSS 4.7EG 4.72025-03-26
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.
- CVE-2024-9666MEDIUMCVSS 4.7EG 4.72024-11-25
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 …
- CVE-2025-52892MEDIUMCVSS 4.5EG 4.52025-08-05
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…
- CVE-2020-5220MEDIUMCVSS 4.4EG 4.42020-01-27
Sylius ResourceBundle accepts and uses any serialisation groups to be passed via a HTTP header. This might lead to data exposure by using an unintended serialisation group - for example it could make Shop API use a more permissive group fr…
- CVE-2020-5218MEDIUMCVSS 4.4EG 4.42020-01-27
Affected versions of Sylius give attackers the ability to switch channels via the _channel_code GET parameter in production environments. This was meant to be enabled only when kernel.debug is set to true. However, if no sylius_channel.deb…
- CVE-2026-20069MEDIUMCVSS 4.3EG 4.32026-03-04
A vulnerability in the VPN web services component of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct browse…
- CVE-2024-42342MEDIUMCVSS 4.3EG 4.32024-09-08
Loway - CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
- CVE-2023-49584MEDIUMCVSS 4.3EG 4.32023-12-12
SAP Fiori launchpad - versions SAP_UI 750, SAP_UI 754, SAP_UI 755, SAP_UI 756, SAP_UI 757, SAP_UI 758, UI_700 200, SAP_BASIS 793, allows an attacker to use HTTP verb POST on read-only service causing low impact on Confidentiality of the ap…
- CVE-2021-32598MEDIUMCVSS 4.3EG 4.32021-08-05
An improper neutralization of CRLF sequences in HTTP headers ('HTTP Response Splitting') vulnerability In FortiManager and FortiAnalyzer GUI 7.0.0, 6.4.6 and below, 6.2.8 and below, 6.0.11 and below, 5.6.11 and below may allow an authentic…
- CVE-2021-33683MEDIUMCVSS 4.3EG 4.32021-07-14
SAP Web Dispatcher and Internet Communication Manager (ICM), versions - KRNL32NUC 7.21, 7.21EXT, 7.22, 7.22EXT, KRNL32UC 7.21, 7.21EXT, 7.22, 7.22EXT, KRNL64NUC 7.21, 7.21EXT, 7.22, 7.22EXT, 7.49, KRNL64UC 7.21, 7.21EXT, 7.22, 7.22EXT, 7.4…
- CVE-2005-2088MEDIUMCVSS v2 4.3EG 4.32005-07-05
The Apache HTTP server before 1.3.34, and 2.0.x before 2.0.55, when acting as an HTTP proxy, allows remote attackers to poison the web cache, bypass web application firewall protection, and conduct XSS attacks via an HTTP request with both…
- CVE-2005-2089MEDIUMCVSS v2 4.3EG 4.32005-07-05
Microsoft IIS 5.0 and 6.0 allows remote attackers to poison the web cache, bypass web application firewall protection, and conduct XSS attacks via an HTTP request with both a "Transfer-Encoding: chunked" header and a Content-Length header,…
- CVE-2019-0197MEDIUMCVSS 4.2EG 4.22019-06-11
A vulnerability was found in Apache HTTP Server 2.4.34 to 2.4.38. When HTTP/2 was enabled for a http: host or H2Upgrade was enabled for h2 on a https: host, an Upgrade request from http/1.1 to http/2 that was not the first request on a con…
- CVE-2026-26365MEDIUMCVSS 4.0EG 4.02026-02-23
Akamai Ghost on Akamai CDN edge servers before 2026-02-06 mishandles processing of custom hop-by-hop HTTP headers, where an incoming request containing the header "Connection: Transfer-Encoding" could result in a forward request with inval…
- CVE-2025-54142MEDIUMCVSS 4.0EG 4.02025-08-29
Akamai Ghost before 2025-07-21 allows HTTP Request Smuggling via an OPTIONS request that has an entity body, because there can be a subsequent request within the persistent connection between an Akamai proxy server and an origin server, if…
- CVE-2025-32094MEDIUMCVSS 4.0EG 4.02025-08-07
An issue was discovered in Akamai Ghost, as used for the Akamai CDN platform before 2025-03-26. Under certain circumstances, a client making an HTTP/1.x OPTIONS request with an "Expect: 100-continue" header, and using obsolete line folding…
- CVE-2026-126406LOWCVSS 3.7EG 3.72026-11-13
The wasmtime-wasi-http p2 implementation in Wasmtime before 36.0.20, 37.0.0 before 48.0.8, 49.0.0 before 49.0.5, and 50.0.0 before 50.0.1 can send conflicting content-length headers, or ones not matching the body, in outgoing requests. A g…
- CVE-2026-121441LOWCVSS 3.7EG 3.72026-11-03
Wasmtime before 36.0.19, 37.0.0 before 48.0.7, and 49.0.0 before 49.0.4 contains a request smuggling vulnerability in wasi-http that allows guests to set multiple conflicting content-length headers. Malicious guests can make the host send …
- CVE-2026-55612LOWCVSS 3.7EG 3.72026-10-30
uhttpd is a small HTTP server. In unpatched repository snapshots, `client_poll_post_data()` in `client.c` consumes an invalid chunk-length line, such as a size exceeding INT_MAX, then clears `r->content_length` and `r->transfer_chunked` wi…
- CVE-2026-77756LOWCVSS 3.7EG 3.72026-09-23
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Apache Tomcat caused by processing the transfer-encoding header for an HTTP/1.0 request may allow an attacker to cause one request from anoth…
- CVE-2026-18540LOWCVSS 3.7EG 3.72026-09-04
undici's retry interceptor can append the body of a ranged retry response to bytes already delivered from an earlier partial response while still presenting the original response's status and headers. This happens when an upstream server d…
- CVE-2026-48932LOWCVSS 3.7EG 3.72026-09-01
A flaw in Node.js HTTP client can cause a request desynchronization for Node.js-based forwarding proxies that rebuild outbound headers from the visible `IncomingMessage` headers while piping the original body to a reused backend connection…
- CVE-2026-58044LOWCVSS 3.7EG 3.72026-08-04
A flaw in Node.js HTTP client can cause a request desynchronization for Node.js-based forwarding proxies that rebuild outbound headers from the visible `IncomingMessage` headers while piping the original body to a reused backend connection…
- CVE-2026-53538LOWCVSS 3.7EG 3.72026-06-15
Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, QuerystringParser treated ; as a field separator in application/x-www-form-urlencoded bodies, in addition to &. The WHATWG URL standard, modern browsers, and Pyt…
- CVE-2025-49005LOWCVSS 3.7EG 3.72025-07-03
Next.js is a React framework for building full-stack web applications. In Next.js App Router from 15.3.0 to before 15.3.3 and Vercel CLI from 41.4.1 to 42.2.0, a cache poisoning vulnerability was found. The issue allowed page requests for …
- CVE-2021-41136LOWCVSS 3.7EG 3.72021-10-12
Puma is a HTTP 1.1 server for Ruby/Rack applications. Prior to versions 5.5.1 and 4.3.9, using `puma` with a proxy which forwards HTTP header values which contain the LF character could allow HTTP request smugggling. A client could smuggle…
- CVE-2026-77803LOWCVSS 3.6EG 3.62026-10-05
In Progress® Telerik® Fiddler® Classic for Windows, versions prior to v6.0.20262.10021, front-end request desynchronization is possible in the proxy request forwarding component. A request that contains both a Content-Length and a Trans…
- CVE-2024-8925LOWCVSS 3.1EG 3.12024-10-08
In PHP versions 8.1.* before 8.1.30, 8.2.* before 8.2.24, 8.3.* before 8.3.12, erroneous parsing of multipart form data contained in an HTTP POST request could lead to legitimate data not being processed. This could lead to malicious atta…
- CVE-2021-32715LOWCVSS 3.1EG 3.12021-07-07
hyper is an HTTP library for rust. hyper's HTTP/1 server code had a flaw that incorrectly parses and accepts requests with a `Content-Length` header with a prefixed plus sign, when it should have been rejected as illegal. This combined wit…
- CVE-2026-55458LOWCVSS 2.9EG 2.92026-10-28
Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.5, the reverse proxy's finalizeResponse method in modules/caddyhttp/reverseproxy/reverseproxy.go handles an upstream 101 Switching Protocols response before run…
- CVE-2026-4742LOWCVSS 2.9EG 2.92026-03-24
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in visualfc liteide (liteidex/src/3rdparty/qjsonrpc/src/http-parser modules). This vulnerability is associated with program files http_parser.C.…
- CVE-2026-50052LOWCVSS 2.3EG 2.32026-06-03
In Vinyl Cache before 9.0.1 and Varnish Cache before 9.0.3, a deficiency in HTTP/2 request parsing can be exploited to launch a backend request desync attack (request smuggling), which in turn can be used for cache poisoning, authenticatio…
- CVE-2026-103995LOWCVSS 2.0EG 2.02026-10-27
Response body and chunk parsing would handle non-hex or negative integers incorrectly which could result in misinterpreting HTTP response contents.
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