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Published vulnerabilities with severity, known exploitation and official sources.
CVE-2026-2835
Critical · 9.1
CWE-444 Mar 4, 2026
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 Transfer-Encoding values, allowing attackers to send HTTP/1.0 requests in a way that would desync Pingora’s request framing from backend servers’.
Impact
This vulnerability primarily affects standalone Pingora deployments in front of certain backends that accept HTTP/1.0 requests. An attacker could craft a malicious payload following this request that Pingora forwards to the backend in order to:
* Bypass proxy-level ACL controls and WAF logic
* Poison caches and upstream connections, causing subsequent requests from legitimate users to receive responses intended for smuggled requests
* Perform cross-user attacks by hijacking sessions or smuggling requests that appear to originate from the trusted proxy IP
Cloudflare's CDN infrastructure was not affected by this vulnerability, as its ingress proxy layers forwarded HTTP/1.1 requests only, rejected ambiguous framing such as invalid Content-Length values, and forwarded a single Transfer-Encoding: chunked header for chunked requests.
Mitigation:
Pingora users should upgrade to Pingora v0.8.0 or higher that fixes this issue by correctly parsing message length headers per RFC 9112 and strictly adhering to more RFC guidelines, including that HTTP request bodies are never close-delimited.
As a workaround, users can reject certain requests with an error in the request filter logic in order to stop processing bytes on the connection and disable downstream connection reuse. The user should reject any non-HTTP/1.1 request, or a request that has invalid Content-Length, multiple Transfer-Encoding headers, or Transfer-Encoding header that is not an exact “chunked” string match.
CVE-2026-2833
Critical · 9.1
CWE-444 Mar 4, 2026
HTTP Request Smuggling via Premature Upgrade
An HTTP request smuggling vulnerability (CWE-444) was found in Pingora's handling of HTTP/1.1 connection upgrades. The issue occurs when a Pingora proxy reads a request containing an Upgrade header, causing the proxy to pass through the rest of the bytes on the connection to a backend before the backend has accepted the upgrade. An attacker can thus directly forward a malicious payload after a request with an Upgrade header to that backend in a way that may be interpreted as a subsequent request header, bypassing proxy-level security controls and enabling cross-user session hijacking.
Impact
This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to:
* Bypass proxy-level ACL controls and WAF logic
* Poison caches and upstream connections, causing subsequent requests from legitimate users to receive responses intended for smuggled requests
* Perform cross-user attacks by hijacking sessions or smuggling requests that appear to originate from the trusted proxy IP
Cloudflare's CDN infrastructure was not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.
Mitigation:
Pingora users should upgrade to Pingora v0.8.0 or higher
As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.
CVE-2026-20069
Medium · 4.3
CWE-444 Mar 4, 2026
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software VPN Web Services Client-Side Request Smuggling Vulnerability
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 browser-based attacks against users of an affected device.
This vulnerability is due to improper validation of HTTP requests. An attacker could exploit this vulnerability by persuading a user to visit a website that is designed to pass malicious HTTP requests to a device that is running Cisco Secure Firewall ASA Software or Cisco Secure FTD Software and has web services endpoints supporting VPN features enabled. A successful exploit could allow the attacker to reflect malicious input from the affected device to the browser that is in use and conduct browser-based attacks, including cross-site scripting (XSS) attacks. The attacker is not able to directly impact the affected device.
CVE-2026-26365
Medium · 4.0
CWE-444 Feb 23, 2026
HTTP Request Smuggling in Akamai Ghost
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 invalid message framing, depending on the Akamai processing path. This could result in the origin server parsing the request body incorrectly, leading to HTTP request smuggling.
CVE-2025-12811
Medium · 6.9
CWE-444 Feb 18, 2026
Cloud Suite and Privilege Access Service– HTTP request smuggling vulnerability
Improper Inconsistent Interpretation of
HTTP Requests ('HTTP Request Smuggling') in Delinea Inc. Cloud Suite and
Privileged Access Service.
If you're not using the latest Server Suite agents, this fix requires that you upgrade to Server Suite 2023.1 (agent 6.0.1) or later. * If you cannot upgrade to Release 2023.1 (agent version 6.0.1) or later, you can choose one of the following versions:
* Server Suite release 2023.0.5 (agent version 6.0.0-158)
* Server Suite release 2022.1.10 (agent version 5.9.1-337)
CVE-2025-55018
Medium · 5.8
CWE-444 Feb 10, 2026
HTTP Request Smuggling in Fortinet Fortios
An inconsistent interpretation of http requests ('http request smuggling') vulnerability in Fortinet FortiOS 7.6.0, FortiOS 7.4.0 through 7.4.9, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4.3 through 6.4.16 may allow an unauthenticated attacker to smuggle an unlogged http request through the firewall policies via a specially crafted header
CVE-2026-1801
Medium · 6.5
CWE-444 Feb 3, 2026
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 feed (LF) characters instead of the required carriage return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP requests from a single network message, potentially leading to information disclosure.
CVE-2026-1760
Medium · 5.3
CWE-444 Feb 2, 2026
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 sending specially crafted requests, causing SoupServer to fail to close the connection as required by RFC 9112. This allows the attacker to smuggle additional requests over the persistent connection, leading to unintended request processing and potential denial-of-service (DoS) conditions.
CVE-2025-41082
Medium · 6.9
CWE-444 Jan 26, 2026
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 between frontend and backend servers, which could allow request hiding, cache poisoning or security bypass.
CVE-2026-1002
Medium · 5.3
CWE-444 Jan 15, 2026
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 fixed in Vert.x Core component (used by Vert.x Web): https://github.com/eclipse-vertx/vert.x/pull/5895
Steps to reproduce
Given a file served by the static handler, craft an URI that introduces a string like bar%2F..%2F after the last / char to deny the access to the URI with an HTTP 404 response. For example https://example.com/foo/index.html can be denied with https://example.com/foo/bar%2F..%2Findex.html
Mitgation
Disabling Static Handler cache fixes the issue.
StaticHandler staticHandler = StaticHandler.create().setCachingEnabled(false);
CVE-2026-23527
Critical · 9.8
CWE-444 Jan 15, 2026
h3 v1 has Request Smuggling (TE.TE) issue
H3 is a minimal H(TTP) framework built for high performance and portability. Prior to 1.15.5, there is a critical HTTP Request Smuggling vulnerability. readRawBody is doing a strict case-sensitive check for the Transfer-Encoding header. It explicitly looks for "chunked", but per the RFC, this header should be case-insensitive. This vulnerability is fixed in 1.15.5.
CVE-2025-69225
Medium · 5.3
CWE-444 Jan 5, 2026
AIOHTTP Regex Mismatch Allows Unicode in ASCII-Only Protocol Fields
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Versions 3.13.2 and below contain parser logic which allows non-ASCII decimals to be present in the Range header. There is no known impact, but there is the possibility that there's a method to exploit a request smuggling vulnerability. This issue is fixed in version 3.13.3.
CVE-2025-69224
Medium · 6.5
CWE-444 Jan 5, 2026
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 installed (i.e. without the usual C extensions) or AIOHTTP_NO_EXTENSIONS is enabled, then an attacker may be able to execute a request smuggling attack to bypass certain firewalls or proxy protections. This issue is fixed in version 3.13.3.
CVE-2025-12874
Medium · 6.3
CWE-444 Dec 19, 2025
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. This could allow an attacker to bypass access controls, poison web caches, hijack sessions, or trigger unintended internal requests. This issue affects Coexistence Manager for Notes 3.8.2045. Other versions may also be affected.
CVE-2023-53878
Medium · 6.9
CWE-444 Dec 15, 2025
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 potentially bypass server-side request processing controls.
CVE-2025-14523
High · 8.2
CWE-444 Dec 11, 2025
Libsoup: libsoup: duplicate host header handling causes host-parsing discrepancy (first- vs last-value wins)
A flaw in libsoup’s HTTP header handling allows multiple Host: headers in a request and returns the last occurrence for server-side processing. Common front proxies often honor the first Host: header, so this mismatch can cause vhost confusion where a proxy routes a request to one backend but the backend interprets it as destined for another host. This discrepancy enables request-smuggling style attacks, cache poisoning, or bypassing host-based access controls when an attacker supplies duplicate Host headers.
CVE-2025-61258
High · 7.5
CWE-444 Dec 9, 2025
HTTP Request Smuggling in Outsystems Platform Server
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-2025-66373
Medium · 4.8
CWE-444 Dec 4, 2025
HTTP Request Smuggling in Akamai Ghost
Akamai Ghost on Akamai CDN edge servers before 2025-11-17 has a chunked request body processing error that can result in HTTP request smuggling. When Akamai Ghost receives an invalid chunked body that includes a chunk size different from the actual size of the following chunk data, under certain circumstances, Akamai Ghost erroneously forwards the invalid request and subsequent superfluous bytes to the origin server. An attacker could hide a smuggled request in these superfluous bytes. Whether this is exploitable depends on the origin server's behavior and how it processes the invalid request it receives from Akamai Ghost.
CVE-2025-12642
Critical · 9.1
CWE-444 Nov 3, 2025
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 input into backend logic that trusts request headers
* Execute HTTP Request Smuggling attacks under some conditions
This issue affects lighttpd1.4.80
CVE-2025-11915
Medium · 6.9
CWE-444 Oct 22, 2025
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.
CVE-2025-55315
Critical · 9.9
Public exploit CWE-444 Oct 14, 2025
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.
CVE-2025-59822
High · 7.5
CWE-444 Sep 23, 2025
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 bypass front-end servers security controls, launch targeted attacks against active users, and poison web caches. A pre-requisite for exploitation involves the web application being deployed behind a reverse-proxy that forwards trailer headers. This issue has been patched in versions 1.0.0-M45 and 0.23.31.
CVE-2025-58056
High · 7.5
CWE-444 Sep 3, 2025
Netty is vulnerable to request smuggling due to incorrect parsing of chunk extensions
Netty is an asynchronous event-driven network application framework for development of maintainable high performance protocol servers and clients. In versions 4.1.124.Final, and 4.2.0.Alpha3 through 4.2.4.Final, Netty incorrectly accepts standalone newline characters (LF) as a chunk-size line terminator, regardless of a preceding carriage return (CR), instead of requiring CRLF per HTTP/1.1 standards. When combined with reverse proxies that parse LF differently (treating it as part of the chunk extension), attackers can craft requests that the proxy sees as one request but Netty processes as two, enabling request smuggling attacks. This is fixed in versions 4.1.125.Final and 4.2.5.Final.
CVE-2025-58068
Critical · 9.1
CWE-444 Aug 29, 2025
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 security controls, launch targeted attacks against active site users, and poison web caches. This problem has been patched in Eventlet 0.40.3 by dropping trailers which is a breaking change if a backend behind eventlet.wsgi proxy requires trailers. A workaround involves not using eventlet.wsgi facing untrusted clients.
CVE-2025-54142
Medium · 4.0
CWE-444 Aug 28, 2025
HTTP Request Smuggling in Akamai Ghost
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 the origin server violates certain Internet standards.