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CWE-444

HTTP Request/Response Smuggling

319 CVEs Avg CVSS 7.0 MITRE
55
CRITICAL
119
HIGH
132
MEDIUM
11
LOW
74
POC
3
KEV

Monthly

CVE-2026-88009 Sep 10, 15:01 HIGH POC PATCH GHSA This Week

HTTP/1 request-target parsing in Traefik prior to 2.11.57 and 3.7.13 allows unauthenticated remote attackers to send a rootless URL target (e.g., `http:example.com/admin`) that Go's HTTP library stores in URL.Opaque rather than URL.Path, leaving URL.Path empty. Traefik's routing engine, forwardAuth middleware, and access logger all evaluate against the normalized empty path (treated as `/`), while URL.RequestURI() gives URL.Opaque precedence when forwarding — meaning the backend receives the original opaque target verbatim. The practical consequence is cross-vhost routing bypass, path-scoped authorization bypass, and access-log evasion, all requiring no authentication or special client configuration. No public exploit has been identified at time of analysis, though the patch PR includes test cases demonstrating the attack technique in full detail.

Authentication Bypass Request Smuggling Traefik
NVD GitHub VulDB
CVSS 4.0
8.8
EPSS
0.3%
CVE-2026-88008 Sep 10, 14:57 HIGH POC PATCH GHSA This Week

Security middleware bypass in Traefik reverse proxy versions 2.11.26-2.11.56 and 3.4.2-3.7.12 allows unauthenticated network attackers to reach protected backend routes by exploiting h2c protocol upgrade tunneling. When a crafted HTTP/1.1 request carrying Connection, Upgrade: h2c, and HTTP2-Settings headers causes a h2c-capable backend to respond with 101 Switching Protocols, Traefik enters a raw TCP tunnel that silently disables every configured middleware layer-including BasicAuth, ForwardAuth, IPAllowList, RateLimit, and all access logging, metrics, and tracing hooks-for the lifetime of that connection. All subsequent HTTP/2 frames in the tunnel reach protected backend paths without any Traefik security enforcement. No public exploit code has been identified at time of analysis; vendor-released fixes are available in v2.11.57 and v3.7.13.

Request Smuggling Traefik
NVD GitHub VulDB
CVSS 4.0
7.0
EPSS
0.4%
CVE-2026-81356 Sep 08, 18:20 HIGH PATCH Exploit Unlikely This Week

HTTP request smuggling in Visual Studio Code (versions 1.0.0 through 1.136.2) enables unauthenticated network attackers to bypass security controls through inconsistent interpretation of HTTP request boundaries. The CVSS scope change (S:C) signals that impact extends beyond the editor itself - smuggled requests can affect back-end services or proxies that VS Code communicates with, resulting in high confidentiality exposure. No public exploit code or CISA KEV listing has been identified at time of analysis, but the network-accessible, unauthenticated nature of the attack surface warrants prompt patching.

Authentication Bypass Microsoft Request Smuggling Visual Studio Code
NVD
CVSS 3.1
8.2
EPSS
0.3%
CVE-2026-19203 Sep 08, 12:08 HIGH This Week

HTTP/1.1 request smuggling in Eclipse Jetty allows unauthenticated remote attackers to desynchronize request boundary parsing between Jetty and an upstream proxy, enabling manipulation of other users' HTTP sessions. The root cause is Jetty's acceptance of a bare LF character (\n) as a line terminator during chunked transfer encoding parsing - specifically in chunk extensions, chunk data termination, or trailer termination - where RFC 7230 mandates CRLF (\r\n). Depending on the Jetty version and configured HTTP compliance mode, a crafted request can cause the proxy and Jetty to disagree on where one request ends and the next begins, enabling request injection against co-located tenants. No public exploit has been identified at time of analysis.

Information Disclosure Request Smuggling Eclipse Jetty Eclipse Foundation
NVD GitHub HeroDevs
CVSS 4.0
8.3
EPSS
0.3%
CVE-2026-73812 Sep 01, 14:42 HIGH PATCH This Week

Request smuggling in Erlang OTP inets (versions 17.0 through 29.x) arises when the httpd server sits behind a Content-Length-preferring reverse proxy: inets frames the request body by chunked Transfer-Encoding and silently discards a co-present Content-Length header, while the front-end proxies request boundaries by Content-Length, producing a classic CL.TE desync. An unauthenticated network attacker in this topology can inject a crafted prefix into a subsequent victim's HTTP request, potentially enabling session hijacking, credential theft, or cache poisoning against other users of the same back-end. No public exploit has been identified at time of analysis, the vulnerability is not listed in CISA KEV, and vendor patches are available for the OTP 27.x, 28.x, and 29.x release branches.

Information Disclosure Red Hat Request Smuggling Otp Suse +1
NVD GitHub VulDB
CVSS 4.0
8.3
EPSS
0.3%
CVE-2026-73276 Sep 01, 14:41 HIGH PATCH This Week

Remote unauthenticated attackers can exploit Erlang/OTP's built-in inets HTTP server across OTP versions 22.2 through 29.0 to conduct HTTP Request Smuggling by sending headers with whitespace before the colon - a malformed construct the server silently discarded rather than rejecting as mandated by RFC 7230 Section 3.2.4. When inets is deployed behind a front-end proxy or load balancer that interprets such headers differently, the resulting parsing discordance creates a desynchronized request boundary exploitable for session hijacking, authentication bypass, or cache poisoning. No public exploit has been identified at time of analysis; vendor-released patches are available across all three affected OTP release branches.

Information Disclosure Red Hat Request Smuggling Otp Suse +1
NVD GitHub VulDB
CVSS 4.0
8.3
EPSS
0.3%
CVE-2026-66357 Sep 01, 14:40 HIGH PATCH This Week

HTTP request smuggling in Erlang/OTP's built-in inets httpd server allows unauthenticated remote attackers to inject arbitrary HTTP headers and poison request pipelines in deployments fronted by a reverse proxy. The root cause is a longstanding absence of obs-fold support: any CRLF followed by a whitespace octet (SP or TAB) is silently parsed as a new header rather than a header continuation, causing proxy-backend disagreement on request boundaries. Affected versions span OTP 17.0 through the patched releases (27.3.4.17, 28.5.0.6, 29.0.6), with vendor patches now available via the Erlang GitHub security advisory. No public exploit code or CISA KEV listing exists at time of analysis.

Information Disclosure Request Smuggling Otp Erlang
NVD GitHub VulDB
CVSS 4.0
8.3
EPSS
0.3%
CVE-2026-74848 Aug 26, 15:24 HIGH This Week

Response poisoning in Apache APISIX 2.12.0 through 3.17.0 enables remote attackers to manipulate the gateway's serverless plugin routes so that victims receive attacker-chosen content or other authenticated users' API responses. The root cause is inconsistent HTTP request boundary interpretation - the defining characteristic of HTTP Request/Response Smuggling - applied within APISIX's serverless plugin execution pipeline. No public exploit has been identified at time of analysis, and vendor-released patch version 3.18.0 is available.

Apache Information Disclosure Request Smuggling Apisix
NVD VulDB
CVSS 4.0
7.0
EPSS
0.4%
CVE-2026-63385 Aug 20, 18:16 CRITICAL PATCH Act Now

HTTP request smuggling and header injection in libevent's http.c allow remote unauthenticated attackers to desynchronize an upstream proxy from libevent's own parsing, bypassing access controls. Affected are all versions prior to 2.1.13-stable and 2.2.2-alpha, where evhttp_header_is_valid_value accepted obsolete CRLF line folding in header values and evhttp_decode_uri_internal decoded %00 into literal NUL bytes that truncate paths in downstream C string operations. No public exploit identified at time of analysis; the CRLF weakness is patched in 2.1.13/2.2.2-alpha, but the URI NUL-truncation condition is not clearly remediated by the reviewed patches.

Authentication Bypass Red Hat Request Smuggling
NVD VulDB GitHub
CVSS 4.0
9.2
EPSS
0.4%
CVE-2026-63382 Aug 20, 17:51 CRITICAL PATCH Act Now

HTTP request smuggling in the libevent evhttp server (http.c) affects all versions prior to 2.1.13 and the 2.2.x-alpha line prior to 2.2.2-alpha, letting an unauthenticated remote attacker desynchronize request boundaries when libevent sits behind a differently-framing proxy. Because evhttp mishandles duplicate and comma-listed Transfer-Encoding headers and accepts bare-LF chunk terminators, a smuggled second request can bypass proxy-enforced access controls or poison shared caches. No public exploit identified at time of analysis, and this is not listed in CISA KEV; a vendor patch is available.

Authentication Bypass Red Hat Request Smuggling Libevent
NVD VulDB GitHub
CVSS 4.0
9.2
EPSS
0.6%
EPSS 0% CVSS 8.8
HIGH POC PATCH This Week

HTTP/1 request-target parsing in Traefik prior to 2.11.57 and 3.7.13 allows unauthenticated remote attackers to send a rootless URL target (e.g., `http:example.com/admin`) that Go's HTTP library stores in URL.Opaque rather than URL.Path, leaving URL.Path empty. Traefik's routing engine, forwardAuth middleware, and access logger all evaluate against the normalized empty path (treated as `/`), while URL.RequestURI() gives URL.Opaque precedence when forwarding — meaning the backend receives the original opaque target verbatim. The practical consequence is cross-vhost routing bypass, path-scoped authorization bypass, and access-log evasion, all requiring no authentication or special client configuration. No public exploit has been identified at time of analysis, though the patch PR includes test cases demonstrating the attack technique in full detail.

Authentication Bypass Request Smuggling Traefik
NVD GitHub VulDB
EPSS 0% CVSS 7.0
HIGH POC PATCH This Week

Security middleware bypass in Traefik reverse proxy versions 2.11.26-2.11.56 and 3.4.2-3.7.12 allows unauthenticated network attackers to reach protected backend routes by exploiting h2c protocol upgrade tunneling. When a crafted HTTP/1.1 request carrying Connection, Upgrade: h2c, and HTTP2-Settings headers causes a h2c-capable backend to respond with 101 Switching Protocols, Traefik enters a raw TCP tunnel that silently disables every configured middleware layer-including BasicAuth, ForwardAuth, IPAllowList, RateLimit, and all access logging, metrics, and tracing hooks-for the lifetime of that connection. All subsequent HTTP/2 frames in the tunnel reach protected backend paths without any Traefik security enforcement. No public exploit code has been identified at time of analysis; vendor-released fixes are available in v2.11.57 and v3.7.13.

Request Smuggling Traefik
NVD GitHub VulDB
EPSS 0% CVSS 8.2
HIGH PATCH Exploit Unlikely This Week

HTTP request smuggling in Visual Studio Code (versions 1.0.0 through 1.136.2) enables unauthenticated network attackers to bypass security controls through inconsistent interpretation of HTTP request boundaries. The CVSS scope change (S:C) signals that impact extends beyond the editor itself - smuggled requests can affect back-end services or proxies that VS Code communicates with, resulting in high confidentiality exposure. No public exploit code or CISA KEV listing has been identified at time of analysis, but the network-accessible, unauthenticated nature of the attack surface warrants prompt patching.

Authentication Bypass Microsoft Request Smuggling +1
NVD
EPSS 0% CVSS 8.3
HIGH This Week

HTTP/1.1 request smuggling in Eclipse Jetty allows unauthenticated remote attackers to desynchronize request boundary parsing between Jetty and an upstream proxy, enabling manipulation of other users' HTTP sessions. The root cause is Jetty's acceptance of a bare LF character (\n) as a line terminator during chunked transfer encoding parsing - specifically in chunk extensions, chunk data termination, or trailer termination - where RFC 7230 mandates CRLF (\r\n). Depending on the Jetty version and configured HTTP compliance mode, a crafted request can cause the proxy and Jetty to disagree on where one request ends and the next begins, enabling request injection against co-located tenants. No public exploit has been identified at time of analysis.

Information Disclosure Request Smuggling Eclipse Jetty +1
NVD GitHub HeroDevs
EPSS 0% CVSS 8.3
HIGH PATCH This Week

Request smuggling in Erlang OTP inets (versions 17.0 through 29.x) arises when the httpd server sits behind a Content-Length-preferring reverse proxy: inets frames the request body by chunked Transfer-Encoding and silently discards a co-present Content-Length header, while the front-end proxies request boundaries by Content-Length, producing a classic CL.TE desync. An unauthenticated network attacker in this topology can inject a crafted prefix into a subsequent victim's HTTP request, potentially enabling session hijacking, credential theft, or cache poisoning against other users of the same back-end. No public exploit has been identified at time of analysis, the vulnerability is not listed in CISA KEV, and vendor patches are available for the OTP 27.x, 28.x, and 29.x release branches.

Information Disclosure Red Hat Request Smuggling +3
NVD GitHub VulDB
EPSS 0% CVSS 8.3
HIGH PATCH This Week

Remote unauthenticated attackers can exploit Erlang/OTP's built-in inets HTTP server across OTP versions 22.2 through 29.0 to conduct HTTP Request Smuggling by sending headers with whitespace before the colon - a malformed construct the server silently discarded rather than rejecting as mandated by RFC 7230 Section 3.2.4. When inets is deployed behind a front-end proxy or load balancer that interprets such headers differently, the resulting parsing discordance creates a desynchronized request boundary exploitable for session hijacking, authentication bypass, or cache poisoning. No public exploit has been identified at time of analysis; vendor-released patches are available across all three affected OTP release branches.

Information Disclosure Red Hat Request Smuggling +3
NVD GitHub VulDB
EPSS 0% CVSS 8.3
HIGH PATCH This Week

HTTP request smuggling in Erlang/OTP's built-in inets httpd server allows unauthenticated remote attackers to inject arbitrary HTTP headers and poison request pipelines in deployments fronted by a reverse proxy. The root cause is a longstanding absence of obs-fold support: any CRLF followed by a whitespace octet (SP or TAB) is silently parsed as a new header rather than a header continuation, causing proxy-backend disagreement on request boundaries. Affected versions span OTP 17.0 through the patched releases (27.3.4.17, 28.5.0.6, 29.0.6), with vendor patches now available via the Erlang GitHub security advisory. No public exploit code or CISA KEV listing exists at time of analysis.

Information Disclosure Request Smuggling Otp +1
NVD GitHub VulDB
EPSS 0% CVSS 7.0
HIGH This Week

Response poisoning in Apache APISIX 2.12.0 through 3.17.0 enables remote attackers to manipulate the gateway's serverless plugin routes so that victims receive attacker-chosen content or other authenticated users' API responses. The root cause is inconsistent HTTP request boundary interpretation - the defining characteristic of HTTP Request/Response Smuggling - applied within APISIX's serverless plugin execution pipeline. No public exploit has been identified at time of analysis, and vendor-released patch version 3.18.0 is available.

Apache Information Disclosure Request Smuggling +1
NVD VulDB
EPSS 0% CVSS 9.2
CRITICAL PATCH Act Now

HTTP request smuggling and header injection in libevent's http.c allow remote unauthenticated attackers to desynchronize an upstream proxy from libevent's own parsing, bypassing access controls. Affected are all versions prior to 2.1.13-stable and 2.2.2-alpha, where evhttp_header_is_valid_value accepted obsolete CRLF line folding in header values and evhttp_decode_uri_internal decoded %00 into literal NUL bytes that truncate paths in downstream C string operations. No public exploit identified at time of analysis; the CRLF weakness is patched in 2.1.13/2.2.2-alpha, but the URI NUL-truncation condition is not clearly remediated by the reviewed patches.

Authentication Bypass Red Hat Request Smuggling
NVD VulDB GitHub
EPSS 1% CVSS 9.2
CRITICAL PATCH Act Now

HTTP request smuggling in the libevent evhttp server (http.c) affects all versions prior to 2.1.13 and the 2.2.x-alpha line prior to 2.2.2-alpha, letting an unauthenticated remote attacker desynchronize request boundaries when libevent sits behind a differently-framing proxy. Because evhttp mishandles duplicate and comma-listed Transfer-Encoding headers and accepts bare-LF chunk terminators, a smuggled second request can bypass proxy-enforced access controls or poison shared caches. No public exploit identified at time of analysis, and this is not listed in CISA KEV; a vendor patch is available.

Authentication Bypass Red Hat Request Smuggling +1
NVD VulDB GitHub

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