Some HTTP/2 implementations are vulnerable to unconstrained interal data buffering, potentially leading to a denial of service. The attacker opens the HTTP/2 window so the peer can send without constraint; however, they leave the TCP window closed so the peer cannot actually write (many of) the bytes on the wire. The attacker then sends a stream of requests for a large response object. Depending on how the servers queue the responses, this can consume excess memory, CPU, or both.

Node.js before 4.8.5, 6.x before 6.11.5, and 8.x before 8.8.0 allows remote attackers to cause a denial of service (uncaught exception and crash) by leveraging a change in the zlib module 1.2.9 making 8 an invalid value for the windowBits parameter.

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.