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...

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...

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...

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...

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'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...

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...