CVE-2021-33587: Css what Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-q8pj-2vqx-8ggc
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CVSS 7.5
CWE-400
Published
Advisory Summary

CVE-2021-33587 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Css what libraries in the npm ecosystem. The issue involves denial of service in css-what. Remediation is available by upgrading affected packages to version 5.0.1.

CVE-2021-33587 at a Glance

CVE Identifier CVE-2021-33587
GHSA Identifier GHSA-q8pj-2vqx-8ggc
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Css what
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2021-33587

To remediate this vulnerability, upgrade all affected Css what dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

css-what fixed: 5.0.1 
npm install css-what@5.0.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls css-what

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-33587, inspect your project dependencies using npm:

npm ls css-what

Analyze the terminal output to locate any version of Css what in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.0.1), your application is affected.

Note: The npm ls css-what command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Css what, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2021-33587 Affected Css what Versions

1 component(s)
Fixed Versions:
5.0.1
Product / Package Ecosystem Affected Versions Fixed Version
css-what
npm/css-what
npm
≥ 4.0.0
< 5.0.1
5.0.1

References

NVD — CVE-2021-33587 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-33587
Security Fix Commit FIX COMMIT
https://github.com/fb55/css-what/commit/4cdaacfd0d4b6fd00614be030da0dea6c2994655
Css what Source Repository REPOSITORY
https://github.com/fb55/css-what
Css what Release RELEASE
https://github.com/fb55/css-what/releases/tag/v5.0.1
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2023/03/msg00001.html
Css what Security Information SECURITY
https://security.netapp.com/advisory/ntap-20210706-0007

Frequently Asked Questions

What is CVE-2021-33587?
CVE-2021-33587 is a security vulnerability in Css what involving Denial of service in css-what under CWE-400: Uncontrolled Resource Consumption.
Which Css what versions are affected?
Affected versions include releases prior to 5.0.1 across affected packages: css-what.
What version fixes CVE-2021-33587?
Upgrading to 5.0.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is css-what affected?
Yes, css-what is affected in releases prior to 5.0.1. Upgrade your dependency to 5.0.1 or later.
What is the CVSS score of CVE-2021-33587?
CVE-2021-33587 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2021-33587?
CVE-2021-33587 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check npm dependencies for CVE-2021-33587?
Run the dependency tree command: 'npm ls css-what'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-q8pj-2vqx-8ggc",
  "modified" : "2021-12-02T17:48:49Z",
  "published" : "2021-06-07T22:11:39Z",
  "aliases" : [ "CVE-2021-33587" ],
  "summary" : "Denial of service in css-what",
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "css-what"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "5.0.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 5.0.0"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-33587"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fb55/css-what/commit/4cdaacfd0d4b6fd00614be030da0dea6c2994655"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/fb55/css-what"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fb55/css-what/releases/tag/v5.0.1"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2023/03/msg00001.html"
  }, {
    "type" : "WEB",
    "url" : "https://security.netapp.com/advisory/ntap-20210706-0007"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-06-01T18:12:32Z",
    "nvd_published_at" : "2021-05-28T20:15:00Z"
  }
}