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: 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.

Node.js: All versions prior to Node.js 6.15.0 and 8.14.0: HTTP request splitting: If Node.js can be convinced to use unsanitized user-provided Unicode data for the `path` option of an HTTP request, then data can be provided which will trigger a second, unexpected, and user-defined HTTP request to made to the same server.

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'.

The OpenSSL DSA signature algorithm has been shown to be vulnerable to a timing side channel attack. An attacker could use variations in the signing algorithm to recover the private key. Fixed in OpenSSL 1.1.1a (Affected 1.1.1). Fixed in OpenSSL 1.1.0j (Affected 1.1.0-1.1.0i). Fixed in OpenSSL 1.0.2q (Affected 1.0.2-1.0.2p).

The OpenSSL ECDSA signature algorithm has been shown to be vulnerable to a timing side channel attack. An attacker could use variations in the signing algorithm to recover the private key. Fixed in OpenSSL 1.1.0j (Affected 1.1.0-1.1.0i). Fixed in OpenSSL 1.1.1a (Affected 1.1.1).

In all versions of Node.js 10 prior to 10.9.0, an argument processing flaw can cause `Buffer.alloc()` to return uninitialized memory. This method is intended to be safe and only return initialized, or cleared, memory. The third argument specifying `encoding` can be passed as a number, this is misinterpreted by `Buffer's` internal "fill" method as the `start` to a fill operation. This flaw may be abused where `Buffer.alloc()` arguments are derived from user input to return uncleared memory blocks that may contain sensitive information.

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.

All versions of Node.js 9.x and 10.x are vulnerable and the severity is HIGH. An attacker can cause a denial of service (DoS) by causing a node process which provides an http server supporting TLS server to crash. This can be accomplished by sending duplicate/unexpected messages during the handshake. This vulnerability has been addressed by updating the TLS implementation.

Node.js versions 9.7.0 and later and 10.x are vulnerable and the severity is MEDIUM. A bug introduced in 9.7.0 increases the memory consumed when reading from the network into JavaScript using the net.Socket object directly as a stream. An attacker could use this cause a denial of service by sending tiny chunks of data in short succession. This vulnerability was restored by reverting to the prior behaviour.