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Fencer Vulns
high 7.5

CVE-2021-33587 json

Denial of service in css-what

published 2021-05-28 5 y ago modified 2026-06-17 4 mo ago also GHSA-q8pj-2vqx-8ggc , EUVD-2021-1380

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

The css-what package 4.0.0 through 5.0.0 for Node.js does not ensure that attribute parsing has Linear Time Complexity relative to the size of the input.

Patch / fix

  • npm css-what 5.0.1
  • node-css-what Debian 14, Debian 13, Debian 12 5.0.1-1

debian advisories DEBIAN-CVE-2021-33587

  • node-css-what Ubuntu 18.04 LTS 2.1.0-1+deb10u1build0.18.04.1
  • node-css-what Ubuntu Pro 16.04 LTS 2.1.0-1ubuntu0.16.04.1~esm1
  • node-css-what Ubuntu Pro 20.04 LTS 3.2.1-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2021-33587

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-33587 updated cvss 7.5

nodejs-css-what: does not ensure that attribute parsing has linear time complexity relative to the size of the input

  • Red Hat OpenShift Service Mesh 2.0 servicemesh-grafana, servicemesh-prometheus, servicemesh-grafana-prometheus Red Hat 3scale API Management Platform 2 system
    affected: no fix available
  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/grc-ui-rhel8, rhacm2/console-rhel8, rhacm2/search-ui-rhel8, rhacm2/console-ui-rhel8, rhacm2/mcm-topology-rhel8, rhacm2/application-ui-rhel8, +2 more Red Hat OpenShift Container Platform 4 openshift4/ose-grafana, openshift4/ose-prometheus, openshift4/ose-thanos-rhel8
    affected: no fix available “Fix deferred”
  • Red Hat Virtualization 4 ovirt-web-ui, ovirt-engine-ui-extensions
    affected: no fix planned “Will not fix”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.04% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
npm css-what
>=4.0.0, <5.0.1
5.0.1

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns 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.