CVE-2026-58055

A flaw in nghttp2's nghttpx proxy allows a remote attacker to perform HTTP request smuggling and cross-client response-queue poisoning. This occurs because the proxy ambiguously forwards HTTP/1.1 Upgrade requests that contain a Content-Length header to reusable keep-alive backend connections...

nghttp2: nghttp2: HTTP Request/Response Smuggling and Response-Queue Poisoning via ambiguous HTTP/1.1 Upgrade requests

A flaw in nghttp2's nghttpx proxy allows a remote attacker to perform HTTP request smuggling and cross-client response-queue poisoning. This occurs because the proxy ambiguously forwards HTTP/1.1 Upgrade requests that contain a Content-Length header to reusable keep-alive backend connections...

OESA-2026-2979 nghttp2 security update

The framing layer of HTTP/2 is implemented as a form of reusable C library. On top of that, we have implemented HTTP/2 client, server and proxy. We have also developed load test and benchmarking tool for HTTP/2. Security Fixes: nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade...

Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : nghttp2 vulnerability (USN-8495-1)

The remote Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-8495-1 advisory. It was discovered that the nghttp2 nghttpx proxy incorrectly handled HTTP/1.1 Upgrade requests that included a Content-Length head...

USN-8495-1: nghttp2 vulnerability

It was discovered that the nghttp2 nghttpx proxy incorrectly handled HTTP/1.1 Upgrade requests that included a Content-Length header and body. A remote attacker could possibly use this issue to perform HTTP request and response smuggling attacks against backend services...

PT-2026-55438

It was discovered that the nghttp2 nghttpx proxy incorrectly handled HTTP/1.1 Upgrade requests that included a Content-Length header and body. A remote attacker could possibly use this issue to perform HTTP request and response smuggling attacks against backend services...

The vulnerability of the nghttpx component in the nghttp2 library, which allows attackers to compromise the confidentiality and integrity of protected information.

The vulnerability of the nghttpx component in the nghttp2 library is related to deficiencies in HTTP request processing. Exploiting this vulnerability allows a malicious actor to compromise the confidentiality and integrity of the protected information...

SUSE CVE-2026-58055

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting...

DEBIAN-CVE-2026-58055

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting...

CVE-2026-58055

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting...

UBUNTU-CVE-2026-58055

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting...

CVE-2026-58055 nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting...

CVE-2026-58055

nghttp2 nghttpx (up to version 1.69.0) is affected. The proxy forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body to reusable keep-alive backend connections, re-adding Upgrade and Connection headers while passing Content-Length verbatim. This creates an ambiguo...

EUVD-2026-39975

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting...

CVE-2026-58055 nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting...

CVE-2026-58055

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting...

CVE-2026-58055

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting...

CVE-2026-58055 nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting...

Linux Distros Unpatched Vulnerability : CVE-2026-58055

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content- Length header and body onto reusable keep-alive backend...

PT-2026-53087

Name of the Vulnerable Software and Affected Versions nghttp2 nghttpx versions prior to 1.69.0 Description The nghttpx proxy forwards HTTP/1.1 Upgrade requests that contain a Content-Length header and body onto reusable keep-alive backend connections. During this process, it re-adds the Upgrade a...