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 is a low-severity HTTP request smuggling vulnerability in aio-libs aiohttp versions prior to 3.13.3. It arises from the parser allowing non-ASCII decimal characters in the HTTP Range header, potentially enabling inconsistent interpretation of HTTP requests. Although no known exploits or impacts have been reported, this flaw could theoretically be leveraged to smuggle HTTP requests, leading to request desynchronization between front-end and back-end servers. The vulnerability is fixed in aiohttp 3.13.3. European organizations using vulnerable aiohttp versions in asynchronous Python web services should upgrade promptly to mitigate risk. Given the low CVSS score and lack of known exploits, the threat is currently low but should not be ignored in sensitive environments.
CVE-2025-69224 is a medium severity HTTP request smuggling vulnerability in aiohttp versions prior to 3.13.3. It affects the Python HTTP parser when non-ASCII characters are present and the pure Python implementation is used (i.e. , without C extensions or when AIOHTTP_NO_EXTENSIONS is enabled). This flaw allows attackers to bypass certain firewalls or proxy protections by crafting malicious HTTP requests that are inconsistently interpreted by intermediaries and the server. Exploitation does not require authentication or user interaction but does require network access to the vulnerable server. No known exploits are currently reported in the wild. The vulnerability impacts confidentiality and integrity by enabling request smuggling attacks that can lead to unauthorized request execution or data leakage.
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.
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.
### Summary
Security-sensitive parts of the *Python HTTP parser* retained minor differences in allowable character sets, that must trigger error handling to robustly match frame boundaries of proxies in order to protect against injection of additional requests. Additionally, validation could trigger exceptions that were not handled consistently with processing of other malformed input.
### Details
These problems are rooted in pattern matching protocol elements, previously improved by PR #3235 and GHSA-gfw2-4jvh-wgfg:
1. The expression `HTTP/(\d).(\d)` lacked another backslash to clarify that the separator should be a literal dot, not just *any* Unicode code point (result: `HTTP/(\d)\.(\d)`).
2. The HTTP version was permitting Unicode digits, where only ASCII digits are standards-compliant.
3. Distinct regular expressions for validating HTTP Method and Header field names were used - though both should (at least) apply the common restrictions of rfc9110 `token`.
### PoC
`GET / HTTP/1ö1`
`GET / HTTP/1.𝟙`
`GET/: HTTP/1.1`
`Content-Encoding?: chunked`
### Impact
Primarily concerns running an aiohttp server without llhttp:
1. **behind a proxy**: Being more lenient than internet standards require could, depending on deployment environment, assist in request smuggling.
2. **directly accessible** or exposed behind proxies relaying malformed input: the unhandled exception could cause excessive resource consumption on the application server and/or its logging facilities.
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Patch: https://github.com/aio-libs/aiohttp/pull/8074/files
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.
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.
An HTTP Request Smuggling [CWE-444] vulnerability in the Authentication portal of WatchGuard Fireware OS allows a remote attacker to evade request parameter sanitation and perform a reflected self-Cross-Site Scripting (XSS) attack.
WatchGuard does not believe there is a practical exploit chain with a meaningful security impact for this vulnerability.
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.
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, can lead to a discrepancy in how two in-path Akamai servers interpret the request, allowing an attacker to smuggle a second request in the original request body.
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.12.14, the Python parser is vulnerable to a request smuggling vulnerability due to not parsing trailer sections of an HTTP request. 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. Version 3.12.14 contains a patch for this issue.
Next.js is a React framework for building full-stack web applications. From versions 15.0.4-canary.51 to before 15.1.8, a cache poisoning bug leading to a Denial of Service (DoS) condition was found in Next.js. This issue does not impact customers hosted on Vercel. Under certain conditions, this issue may allow a HTTP 204 response to be cached for static pages, leading to the 204 response being served to all users attempting to access the page. This issue has been addressed in version 15.1.8.
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 HTML content to return a React Server Component (RSC) payload instead under certain conditions. When deployed to Vercel, this would only impact the browser cache, and would not lead to the CDN being poisoned. When self-hosted and deployed externally, this could lead to cache poisoning if the CDN does not properly distinguish between RSC / HTML in the cache keys. This issue has been resolved in Next.js 15.3.3.
Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.
The specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.
CVE-2024-33452 is a high-severity vulnerability in OpenResty lua-nginx-module version 0.10.26 and earlier. It allows a remote attacker to perform HTTP request smuggling by sending a specially crafted HEAD request. This can lead to impacts on confidentiality, integrity, and availability of the affected system.
The net/http package improperly accepts a bare LF as a line terminator in chunked data chunk-size lines. This can permit request smuggling if a net/http server is used in conjunction with a server that incorrectly accepts a bare LF as part of a chunk-ext.
Gunicorn version 21.2.0 does not properly validate the value of the 'Transfer-Encoding' header as specified in the RFC standards, which leads to the default fallback method of 'Content-Length,' making it vulnerable to TE.CL request smuggling. This vulnerability can lead to cache poisoning, data exposure, session manipulation, SSRF, XSS, DoS, data integrity compromise, security bypass, information leakage, and business logic abuse.
CVE-2024-12397 is a vulnerability in Quarkus-HTTP where the software incorrectly parses cookies containing certain value-delimiting characters. This flaw allows attackers to craft cookie values that can exfiltrate HttpOnly cookies or spoof additional cookie values, potentially leading to unauthorized data access or modification. The vulnerability impacts data confidentiality and integrity. It has a CVSS score of 7.4 (high severity). Red Hat has issued advisories related to this CVE in their build of Keycloak 26.2.4, providing updated packages and container images that address the issue.
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 non-IP values, such as obfuscated identifiers, without proper validation. This issue can lead to costly DNS resolution operations, which an attacker could exploit to tie up IO threads and potentially cause a denial of service.
The attacker must have access to send requests to a Keycloak instance that is configured to accept proxy headers, specifically when reverse proxies do not overwrite incoming headers, and Keycloak is configured to trust these headers.