A flaw was found in the Node.js code where a specially crafted HTTP request sent to a Node.js server failed to properly process the HTTP headers, resulting in a request smuggling attack. An attacker can use this flaw to alter a request sent as an authenticated user if the Node.js server is deployed behind a proxy server that reuses connections. Node.js: All versions prior to Node.js 6.15.0, 8.14.0, 10.14.0 and 11.3.0: Denial of Service with large HTTP headers: By using a combination of many requests with maximum sized headers , and carefully timed completion of the headers, it is possible to cause the HTTP server to abort from heap allocation failure. Attack potential is mitigated by the use of a load balancer or other proxy layer. It was found that the http module from Node.js could accept incorrect Content-Length values, containing spaces within the value, in HTTP headers. A specially crafted client could use this flaw to possibly confuse the script, causing unspecified behavior