CVE-2019-15605: 
npm vulnerability analysis and mitigation

CVE-2019-15605 is a critical security vulnerability affecting Node.js versions 10, 12, and 13 that was discovered in 2019 and patched in February 2020. The vulnerability allows HTTP request smuggling attacks when the Transfer-Encoding header is malformed, potentially enabling attackers to deliver malicious payloads to unsuspecting users (NodeJS Blog).

The vulnerability exists in Node.js's HTTP parsing functionality where a specially crafted HTTP(s) request sent to a Node.js server fails to properly process malformed Transfer-Encoding headers. This vulnerability has been assigned a CVSS v3.1 base score of 9.8 (CRITICAL), indicating the highest severity level (Red Hat).

Successful exploitation of this vulnerability could allow attackers to perform HTTP request smuggling attacks and deliver malicious payloads to users. The payloads can be crafted to hijack user sessions, poison cookies, perform clickjacking, and execute various other attacks depending on the underlying system architecture (NodeJS Blog).

The vulnerability has been fixed in Node.js versions 10.19.0, 12.15.0, and 13.8.0. Users should upgrade to these or later versions. Additionally, HTTP parsing has been made more strict to enhance security. For cases where interoperability with non-conformant HTTP implementations is required, the --insecure-http-parser command line flag or insecureHTTPParser http option can be used, though this is not recommended (NodeJS Blog).