Unrated
HTTP/1 server connection desynchronization after 2xx CONNECT response in net/http
When an HTTP server handler sends a 2xx response to an HTTP/1 CONNECT request and returns without hijacking the connection, the server improperly continues to read and serve requests from the connection. Since a 2xx response to an HTTP/1 CONNECT converts the connection into a tunnel, the server should not treat the connection as continuing to contain HTTP. The impact of this misbehavior is mostly limited to potential request smuggling, where an intermediate proxy considers the data on the connection to be tunneled and the server considers it to be HTTP.
Announced Group revision 1
Original source ↗CVE-2026-94439
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-94439
net/http
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "Go standard library",
"product": "net/http",
"versions": [
{
"status": "affected",
"version": "0",
"lessThan": "1.26.9",
"versionType": "semver"
},
{
"status": "affected",
"version": "1.27.0-0",
"lessThan": "1.27.2",
"versionType": "semver"
}
],
"packageName": "net/http",
"collectionURL": "https://pkg.go.dev",
"defaultStatus": "unaffected",
"programRoutines": [
{
"name": "chunkWriter.writeHeader"
},
{
"name": "CanonicalHeaderKey"
},
{
"name": "Client.CloseIdleConnections"
},
{
"name": "Client.Do"
},
{
"name": "Client.Get"
},
{
"name": "Client.Head"
},
{
"name": "Client.Post"
},
{
"name": "Client.PostForm"
},
{
"name": "ClientConn.Close"
},
{
"name": "ClientConn.RoundTrip"
},
{
"name": "Cookie.String"
},
{
"name": "Cookie.Valid"
},
{
"name": "CrossOriginProtection.AddInsecureBypassPattern"
},
{
"name": "CrossOriginProtection.AddTrustedOrigin"
},
{
"name": "CrossOriginProtection.Check"
},
{
"name": "Dir.Open"
},
{
"name": "Error"
},
{
"name": "Get"
},
{
"name": "Handle"
},
{
"name": "HandleFunc"
},
{
"name": "HandlerFunc.ServeHTTP"
},
{
"name": "Head"
},
{
"name": "Header.Add"
},
{
"name": "Header.Del"
},
{
"name": "Header.Get"
},
{
"name": "Header.Set"
},
{
"name": "Header.Values"
},
{
"name": "Header.Write"
},
{
"name": "Header.WriteSubset"
},
{
"name": "ListenAndServe"
},
{
"name": "ListenAndServeTLS"
},
{
"name": "NewRequest"
},
{
"name": "NewRequestWithContext"
},
{
"name": "NotFound"
},
{
"name": "ParseCookie"
},
{
"name": "ParseSetCookie"
},
{
"name": "ParseTime"
},
{
"name": "Post"
},
{
"name": "PostForm"
},
{
"name": "ProxyFromEnvironment"
},
{
"name": "ReadRequest"
},
{
"name": "ReadResponse"
},
{
"name": "Redirect"
},
{
"name": "Request.AddCookie"
},
{
"name": "Request.BasicAuth"
},
{
"name": "Request.Cookie"
},
{
"name": "Request.Cookies"
},
{
"name": "Request.CookiesNamed"
},
{
"name": "Request.FormFile"
},
{
"name": "Request.FormValue"
},
{
"name": "Request.MultipartReader"
},
{
"name": "Request.ParseForm"
},
{
"name": "Request.ParseMultipartForm"
},
{
"name": "Request.PostFormValue"
},
{
"name": "Request.Referer"
},
{
"name": "Request.SetBasicAuth"
},
{
"name": "Request.UserAgent"
},
{
"name": "Request.Write"
},
{
"name": "Request.WriteProxy"
},
{
"name": "Response.Cookies"
},
{
"name": "Response.Location"
},
{
"name": "Response.Write"
},
{
"name": "ResponseController.EnableFullDuplex"
},
{
"name": "ResponseController.Flush"
},
{
"name": "ResponseController.Hijack"
},
{
"name": "ResponseController.SetReadDeadline"
},
{
"name": "ResponseController.SetWriteDeadline"
},
{
"name": "Serve"
},
{
"name": "ServeContent"
},
{
"name": "ServeFile"
},
{
"name": "ServeFileFS"
},
{
"name": "ServeMux.Handle"
},
{
"name": "ServeMux.HandleFunc"
},
{
"name": "ServeMux.ServeHTTP"
},
{
"name": "ServeTLS"
},
{
"name": "Server.Close"
},
{
"name": "Server.ListenAndServe"
},
{
"name": "Server.ListenAndServeTLS"
},
{
"name": "Server.Serve"
},
{
"name": "Server.ServeTLS"
},
{
"name": "Server.SetKeepAlivesEnabled"
},
{
"name": "Server.Shutdown"
},
{
"name": "SetCookie"
},
{
"name": "Transport.CancelRequest"
},
{
"name": "Transport.Clone"
},
{
"name": "Transport.CloseIdleConnections"
},
{
"name": "Transport.NewClientConn"
},
{
"name": "Transport.RoundTrip"
},
{
"name": "body.Close"
},
{
"name": "body.Read"
},
{
"name": "bodyEOFSignal.Close"
},
{
"name": "bodyEOFSignal.Read"
},
{
"name": "bodyLocked.Read"
},
{
"name": "bufioFlushWriter.Write"
},
{
"name": "cancelTimerBody.Close"
},
{
"name": "cancelTimerBody.Read"
},
{
"name": "checkConnErrorWriter.Write"
},
{
"name": "chunkWriter.Write"
},
{
"name": "connReader.Read"
},
{
"name": "connectMethodKey.String"
},
{
"name": "expectContinueReader.Close"
},
{
"name": "expectContinueReader.Read"
},
{
"name": "extraHeader.Write"
},
{
"name": "fileHandler.ServeHTTP"
},
{
"name": "fileTransport.RoundTrip"
},
{
"name": "globalOptionsHandler.ServeHTTP"
},
{
"name": "gzipReader.Close"
},
{
"name": "gzipReader.Read"
},
{
"name": "http1ClientConn.Close"
},
{
"name": "http1ClientConn.RoundTrip"
},
{
"name": "http2ClientConn.RoundTrip"
},
{
"name": "http2Handler.ServeHTTP"
},
{
"name": "http2ResponseWriter.Flush"
},
{
"name": "http2ResponseWriter.FlushError"
},
{
"name": "http2ResponseWriter.Push"
},
{
"name": "http2RoundTripper.RoundTrip"
},
{
"name": "http3ServerHandler.ServeHTTP"
},
{
"name": "initALPNRequest.ServeHTTP"
},
{
"name": "loggingConn.Close"
},
{
"name": "loggingConn.Read"
},
{
"name": "loggingConn.Write"
},
{
"name": "maxBytesReader.Close"
},
{
"name": "maxBytesReader.Read"
},
{
"name": "onceCloseListener.Close"
},
{
"name": "persistConn.Read"
},
{
"name": "persistConnWriter.ReadFrom"
},
{
"name": "persistConnWriter.Write"
},
{
"name": "populateResponse.Write"
},
{
"name": "populateResponse.WriteHeader"
},
{
"name": "readTrackingBody.Close"
},
{
"name": "readTrackingBody.Read"
},
{
"name": "readWriteCloserBody.CloseWrite"
},
{
"name": "readWriteCloserBody.Read"
},
{
"name": "redirectHandler.ServeHTTP"
},
{
"name": "response.Flush"
},
{
"name": "response.FlushError"
},
{
"name": "response.Hijack"
},
{
"name": "response.ReadFrom"
},
{
"name": "response.Write"
},
{
"name": "response.WriteHeader"
},
{
"name": "response.WriteString"
},
{
"name": "serverHandler.ServeHTTP"
},
{
"name": "socksDialer.DialWithConn"
},
{
"name": "socksUsernamePassword.Authenticate"
},
{
"name": "stringWriter.WriteString"
},
{
"name": "timeoutHandler.ServeHTTP"
},
{
"name": "timeoutWriter.Write"
},
{
"name": "timeoutWriter.WriteHeader"
},
{
"name": "transportReadFromServerError.Error"
},
{
"name": "unencryptedHTTP2Request.ServeHTTP"
}
]
}
]- Related CVEs
- CVE-2026-94439
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #16391 · Revision 1
- Added to Heist Feed
- Publisher date