Keep-alive HTTP and HTTPS connections can remain open and inactive for up to 2 minutes in Node.js 6.16.0 and earlier. Node.js 8.0.0 introduced a dedicated server.keepAliveTimeout which defaults to 5 seconds. The behavior in Node.js 6.16.0 and earlier is a potential Denial of Service (DoS) attack vector. Node.js 6.17.0 introduces server.keepAliveTimeout and the 5-second default.

In Node.js including 6.x before 6.17.0, 8.x before 8.15.1, 10.x before 10.15.2, and 11.x before 11.10.1, an attacker can cause a Denial of Service (DoS) by establishing an HTTP or HTTPS connection in keep-alive mode and by sending headers very slowly. This keeps the connection and associated resources alive for a long period of time. Potential attacks are mitigated by the use of a load balancer or other proxy layer. This vulnerability is an extension of CVE-2018-12121, addressed in November and impacts all active Node.js release lines including 6.x before 6.17.0, 8.x before 8.15.1, 10.x before 10.15.2, and 11.x before 11.10.1.

Node.js: All versions prior to Node.js 6.15.0, 8.14.0, 10.14.0 and 11.3.0: Hostname spoofing in URL parser for javascript protocol: If a Node.js application is using url.parse() to determine the URL hostname, that hostname can be spoofed by using a mixed case "javascript:" (e.g. "javAscript:") protocol (other protocols are not affected). If security decisions are made about the URL based on the hostname, they may be incorrect.

Node.js: All versions prior to Node.js 6.15.0, 8.14.0, 10.14.0 and 11.3.0: Slowloris HTTP Denial of Service: An attacker can cause a Denial of Service (DoS) by sending headers very slowly keeping HTTP or HTTPS connections and associated resources alive for a long period of time.

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 (almost 80 KB per connection), 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.

Node.js: All versions prior to Node.js 6.15.0: Debugger port 5858 listens on any interface by default: When the debugger is enabled with `node --debug` or `node debug`, it listens to port 5858 on all interfaces by default. This may allow remote computers to attach to the debug port and evaluate arbitrary JavaScript. The default interface is now localhost. It has always been possible to start the debugger on a specific interface, such as `node --debug=localhost`. The debugger was removed in Node.js 8 and replaced with the inspector, so no versions from 8 and later are vulnerable.

Simultaneous Multi-threading (SMT) in processors can enable local users to exploit software vulnerable to timing attacks via a side-channel timing attack on 'port contention'.

In all versions of Node.js prior to 6.14.4, 8.11.4 and 10.9.0 when used with UCS-2 encoding (recognized by Node.js under the names `'ucs2'`, `'ucs-2'`, `'utf16le'` and `'utf-16le'`), `Buffer#write()` can be abused to write outside of the bounds of a single `Buffer`. Writes that start from the second-to-last position of a buffer cause a miscalculation of the maximum length of the input bytes to be written.

Node.js v4.0 through v4.8.3, all versions of v5.x, v6.0 through v6.11.0, v7.0 through v7.10.0, and v8.0 through v8.1.3 was susceptible to hash flooding remote DoS attacks as the HashTable seed was constant across a given released version of Node.js. This was a result of building with V8 snapshots enabled by default which caused the initially randomized seed to be overwritten on startup.

The tls.checkServerIdentity function in Node.js 0.10.x before 0.10.47, 0.12.x before 0.12.16, 4.x before 4.6.0, and 6.x before 6.7.0 does not properly handle wildcards in name fields of X.509 certificates, which allows man-in-the-middle attackers to spoof servers via a crafted certificate.

CRLF injection vulnerability in the ServerResponse#writeHead function in Node.js 0.10.x before 0.10.47, 0.12.x before 0.12.16, 4.x before 4.6.0, and 6.x before 6.7.0 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via the reason argument.

Integer overflow in the MDC2_Update function in crypto/mdc2/mdc2dgst.c in OpenSSL before 1.1.0 allows remote attackers to cause a denial of service (out-of-bounds write and application crash) or possibly have unspecified other impact via unknown vectors.