CVE-2021-23639: Md to pdf Code Injection Vulnerability

CRITICAL
Advisory Identifier: GHSA-x949-7cm6-fm6p
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CVSS 9.8
CWE-94
Published
Advisory Summary

CVE-2021-23639 is a CRITICAL (CVSS 9.8) code injection vulnerability (CWE-94: Improper Control of Generation of Code ('Code Injection')) affecting Md to pdf libraries in the npm ecosystem. The issue involves code injection in md-to-pdf.. Remediation is available by upgrading affected packages to version 5.0.0.

CVE-2021-23639 at a Glance

CVE Identifier CVE-2021-23639
GHSA Identifier GHSA-x949-7cm6-fm6p
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-94: Improper Control of Generation of Code ('Code Injection')
Affected Product Md to pdf
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 9.8

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:H/I:H/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 High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2021-23639

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

md-to-pdf fixed: 5.0.0 
npm install md-to-pdf@5.0.0
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 md-to-pdf

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-23639, inspect your project dependencies using npm:

npm ls md-to-pdf

Analyze the terminal output to locate any version of Md to pdf in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 5.0.0), your application is affected.

Note: The npm ls md-to-pdf 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-94: Improper Control of Generation of Code ('Code Injection'), where the product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. In Md to pdf, 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 package md-to-pdf before 5.0.0 are vulnerable to Remote Code Execution (RCE) due to utilizing the library gray-matter to parse front matter content, without disabling the JS engine.

CVE-2021-23639 Affected Md to pdf Versions

1 component(s)
Fixed Versions:
5.0.0
Product / Package Ecosystem Affected Versions Fixed Version
md-to-pdf
npm/md-to-pdf
npm
< 5.0.0
5.0.0

References

NVD — CVE-2021-23639 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-23639
Md to pdf Source Repository REPOSITORY
https://github.com/simonhaenisch/md-to-pdf/issues/99
Security Fix Commit FIX COMMIT
https://github.com/simonhaenisch/md-to-pdf/commit/a716259c548c82fa1d3b14a3422e9100619d2d8a
Md to pdf Source Repository REPOSITORY
https://github.com/simonhaenisch/md-to-pdf
snyk.io/vuln/snyk-js-mdtopd... WEB
https://snyk.io/vuln/SNYK-JS-MDTOPDF-1657880

Frequently Asked Questions

What is CVE-2021-23639?
CVE-2021-23639 is a security vulnerability in Md to pdf involving Code Injection in md-to-pdf. under CWE-94: Improper Control of Generation of Code ('Code Injection').
Which Md to pdf versions are affected?
Affected versions include releases prior to 5.0.0 across affected packages: md-to-pdf.
What version fixes CVE-2021-23639?
Upgrading to 5.0.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is md-to-pdf affected?
Yes, md-to-pdf is affected in releases prior to 5.0.0. Upgrade your dependency to 5.0.0 or later.
What is the CVSS score of CVE-2021-23639?
CVE-2021-23639 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2021-23639?
CVE-2021-23639 is classified under CWE-94: Improper Control of Generation of Code ('Code Injection') (The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.).
How can I check npm dependencies for CVE-2021-23639?
Run the dependency tree command: 'npm ls md-to-pdf'. 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-x949-7cm6-fm6p",
  "modified" : "2021-12-15T15:22:46Z",
  "published" : "2021-12-16T14:34:40Z",
  "aliases" : [ "CVE-2021-23639" ],
  "summary" : "Code Injection in md-to-pdf.",
  "details" : "The package md-to-pdf before 5.0.0 are vulnerable to Remote Code Execution (RCE) due to utilizing the library gray-matter to parse front matter content, without disabling the JS engine.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "md-to-pdf"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "5.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-23639"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/simonhaenisch/md-to-pdf/issues/99"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/simonhaenisch/md-to-pdf/commit/a716259c548c82fa1d3b14a3422e9100619d2d8a"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/simonhaenisch/md-to-pdf"
  }, {
    "type" : "WEB",
    "url" : "https://snyk.io/vuln/SNYK-JS-MDTOPDF-1657880"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-94" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-12-14T14:31:35Z",
    "nvd_published_at" : "2021-12-10T20:15:00Z"
  }
}