CVE-2021-3801: Prismjs Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-hqhp-5p83-hx96
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CVSS 6.5
CWE-400
Published
Advisory Summary

CVE-2021-3801 is a MODERATE (CVSS 6.5) denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Prismjs libraries in the npm ecosystem. The issue involves prismjs regular expression denial of service vulnerability. Remediation is available by upgrading affected packages to version 1.25.0.

CVE-2021-3801 at a Glance

CVE Identifier CVE-2021-3801
GHSA Identifier GHSA-hqhp-5p83-hx96
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Prismjs
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 6.5

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:R/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 Required (UI:R)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2021-3801

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

prismjs fixed: 1.25.0 
npm install prismjs@1.25.0
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 prismjs

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-3801, inspect your project dependencies using npm:

npm ls prismjs

Analyze the terminal output to locate any version of Prismjs in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.25.0), your application is affected.

Note: The npm ls prismjs 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 Prismjs, 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

Prism is a syntax highlighting library. The prismjs package is vulnerable to ReDoS (regular expression denial of service). An attacker that is able to provide a crafted HTML comment as input may cause an application to consume an excessive amount of CPU.

CVE-2021-3801 Affected Prismjs Versions

1 component(s)
Fixed Versions:
1.25.0
Product / Package Ecosystem Affected Versions Fixed Version
prismjs
npm/prismjs
npm
< 1.25.0
1.25.0

References

NVD — CVE-2021-3801 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-3801
Security Fix Commit FIX COMMIT
https://github.com/prismjs/prism/commit/0ff371bb4775a131634f47d0fe85794c547232f9
Prismjs Source Repository REPOSITORY
https://github.com/prismjs/prism
huntr.dev/bounties/8c16ab31-6... WEB
https://huntr.dev/bounties/8c16ab31-6eb6-46d1-b9a4-387222fe1b8a

Frequently Asked Questions

What is CVE-2021-3801?
CVE-2021-3801 is a security vulnerability in Prismjs involving prismjs Regular Expression Denial of Service vulnerability under CWE-400: Uncontrolled Resource Consumption.
Which Prismjs versions are affected?
Affected versions include releases prior to 1.25.0 across affected packages: prismjs.
What version fixes CVE-2021-3801?
Upgrading to 1.25.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is prismjs affected?
Yes, prismjs is affected in releases prior to 1.25.0. Upgrade your dependency to 1.25.0 or later.
What is the CVSS score of CVE-2021-3801?
CVE-2021-3801 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2021-3801?
CVE-2021-3801 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-2021-3801?
Run the dependency tree command: 'npm ls prismjs'. 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-hqhp-5p83-hx96",
  "modified" : "2022-08-10T23:38:25Z",
  "published" : "2021-09-20T20:44:48Z",
  "aliases" : [ "CVE-2021-3801" ],
  "summary" : "prismjs Regular Expression Denial of Service vulnerability",
  "details" : "Prism is a syntax highlighting library. The prismjs package is vulnerable to ReDoS (regular expression denial of service). An attacker that is able to provide a crafted HTML comment as input may cause an application to consume an excessive amount of CPU.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "prismjs"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.25.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-3801"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/prismjs/prism/commit/0ff371bb4775a131634f47d0fe85794c547232f9"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/prismjs/prism"
  }, {
    "type" : "WEB",
    "url" : "https://huntr.dev/bounties/8c16ab31-6eb6-46d1-b9a4-387222fe1b8a"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-09-16T18:29:46Z",
    "nvd_published_at" : "2021-09-15T13:15:00Z"
  }
}