CVE-2021-21306: Marked Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-4r62-v4vq-hr96
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CVSS 5.3
CWE-400
Published
Advisory Summary

CVE-2021-21306 is a MODERATE (CVSS 5.3) denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Marked libraries in the npm ecosystem. The issue involves regular expression denial of service (redos) in marked. Remediation is available by upgrading affected packages to version 2.0.0.

CVE-2021-21306 at a Glance

CVE Identifier CVE-2021-21306
GHSA Identifier GHSA-4r62-v4vq-hr96
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Marked
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.3

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:L).

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 Low (A:L)

How to Fix CVE-2021-21306

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

marked fixed: 2.0.0 
npm install marked@2.0.0
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 marked

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-21306, inspect your project dependencies using npm:

npm ls marked

Analyze the terminal output to locate any version of Marked in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.0.0), your application is affected.

Note: The npm ls marked 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 Marked, 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

### Impact _What kind of vulnerability is it? Who is impacted?_ [Regular expression Denial of Service](https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS) A Denial of Service attack can affect anyone who runs user generated code through `marked`. ### Patches _Has the problem been patched? What versions should users upgrade to?_ patched in v2.0.0 ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ None. ### References _Are there any links users can visit to find out more?_ https://github.com/markedjs/marked/issues/1927 https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS ### For more information If you have any questions or comments about this advisory: * Open an issue in [marked](https://github.com/markedjs/marked/issues)

CVE-2021-21306 Affected Marked Versions

1 component(s)
Fixed Versions:
2.0.0
Product / Package Ecosystem Affected Versions Fixed Version
marked
npm/marked
npm
≥ 1.1.1
< 2.0.0
2.0.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/markedjs/marked/security/advisories/GHSA-4r62-v4vq-hr96
NVD — CVE-2021-21306 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-21306
Marked Source Repository REPOSITORY
https://github.com/markedjs/marked/issues/1927
Marked Source Repository REPOSITORY
https://github.com/markedjs/marked/pull/1864
Security Fix Commit FIX COMMIT
https://github.com/markedjs/marked/commit/7293251c438e3ee968970f7609f1a27f9007bccd
www.npmjs.com/package/marked WEB
https://www.npmjs.com/package/marked

Frequently Asked Questions

What is CVE-2021-21306?
CVE-2021-21306 is a security vulnerability in Marked involving Regular Expression Denial of Service (REDoS) in Marked under CWE-400: Uncontrolled Resource Consumption.
Which Marked versions are affected?
Affected versions include releases prior to 2.0.0 across affected packages: marked.
What version fixes CVE-2021-21306?
Upgrading to 2.0.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is marked affected?
Yes, marked is affected in releases prior to 2.0.0. Upgrade your dependency to 2.0.0 or later.
What is the CVSS score of CVE-2021-21306?
CVE-2021-21306 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2021-21306?
CVE-2021-21306 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-2021-21306?
Run the dependency tree command: 'npm ls marked'. 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-4r62-v4vq-hr96",
  "modified" : "2021-02-08T21:17:26Z",
  "published" : "2021-02-08T21:17:58Z",
  "aliases" : [ "CVE-2021-21306" ],
  "summary" : "Regular Expression Denial of Service (REDoS) in Marked",
  "details" : "### Impact\n_What kind of vulnerability is it? Who is impacted?_\n\n[Regular expression Denial of Service](https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS)\n\nA Denial of Service attack can affect anyone who runs user generated code through `marked`.\n\n### Patches\n_Has the problem been patched? What versions should users upgrade to?_\n\npatched in v2.0.0\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\n\nNone.\n\n### References\n_Are there any links users can visit to find out more?_\n\nhttps://github.com/markedjs/marked/issues/1927\nhttps://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [marked](https://github.com/markedjs/marked/issues)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "marked"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.1.1"
      }, {
        "fixed" : "2.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/markedjs/marked/security/advisories/GHSA-4r62-v4vq-hr96"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-21306"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/markedjs/marked/issues/1927"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/markedjs/marked/pull/1864"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/markedjs/marked/commit/7293251c438e3ee968970f7609f1a27f9007bccd"
  }, {
    "type" : "WEB",
    "url" : "https://www.npmjs.com/package/marked"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-02-08T21:17:26Z",
    "nvd_published_at" : "2021-02-08T22:15:00Z"
  }
}