Denial of Service in uws

published 2018-05-31 8 y ago modified 2026-06-17 4 mo ago also GHSA-hf5h-hh56-3vrg , EUVD-2020-1096

cvss: 5.9; version 3.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.3%; EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits: 0; none known

uws is a WebSocket server library. By sending a 256mb websocket message to a uws server instance with permessage-deflate enabled, there is a possibility used compression will shrink said 256mb down to less than 16mb of websocket payload which passes the length check of 16mb payload. This data will then inflate up to 256mb and crash the node process by exceeding V8's maximum string size. This affects uws >=0.10.0 <=0.10.8.

Patch / fix

fixed in 1 links 1

npm uws 0.10.9

github.com/uWebSockets/uWebSockets@37deefd commit

Exploit prediction

1.29% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.0	5.9	CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:N/I:N/A:P

Affected packages

ecosystem	package	affected	fixed in
npm	uws	>=0.10.0, <0.10.9	0.10.9

Affected products

HackerOne uws node module

Classification

Weakness

CWE-400 Uncontrolled Resource Consumption
CWE-20 Improper Input Validation

References

github.com /uWebSockets/uWebSockets/commit/37deefd01f0875e133ea967122e3a5e421b8fcd9
web, patch, third-party-advisory
nodesecurity.io /advisories/149
third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2016-10544
advisory
npmjs.com /advisories/149
web

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary