CVE-2021-33587

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.

Published: 2021-05-28 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-33587 is rated Moderate Risk (44.3/100): CVSS High severity, with low exploitation likelihood (EPSS 0.19%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-33587

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-22 0.30% 0.19% -0.11%
2 2026-04-16 0.21% 0.30% +0.09%
3 2025-11-21 — 0.21% —

Full EPSS history (18 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-33587

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-33587

GitHub Security Advisory for CVE-2021-33587

OS Trackers for CVE-2021-33587

vendor priority summary link
debian not yet assigned CVE-2021-33587 not yet assigned priority: Debian including 1 source packages (node-css-what), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-33587
redhat medium — https://access.redhat.com/security/cve/CVE-2021-33587
ubuntu medium CVE-2021-33587 medium priority: Ubuntu including 1 source packages (node-css-what), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 6, needs-triage 3, not-affected 3, released 3, DNE 1. https://ubuntu.com/security/CVE-2021-33587

Affected software / configurations for CVE-2021-33587

Vendor Product Version Raw CPE
css-what_project css-what 4.0.0 cpe:2.3:a:css-what_project:css-what:4.0.0:*:*:*:*:node.js:*:*
css-what_project css-what 5.0.0 cpe:2.3:a:css-what_project:css-what:5.0.0:*:*:*:*:node.js:*:*
netapp e-series_performance_analyzer — cpe:2.3:a:netapp:e-series_performance_analyzer:-:*:*:*:*:*:*:*

References for CVE-2021-33587

cvelogic Threat Intelligence