CVE-2025-65108

A Markdown front-matter block that contains JavaScript delimiter causes the JS engine in gray-matter library to execute arbitrary code in the Markdown to PDF converter process of md-to-pdf library, resulting in remote code execution.

Details

md-to-pdf uses the gray-matter library to parse front-matter. Gray-matter exposes a JavaScript engine that, when enabled or triggered by certain front-matter delimiters (e.g. ---js or ---javascript), will evaluate the front-matter contents as JavaScript. If user-supplied Markdown is fed to md-to-pdf and the front-matter contains malicious JS, the converter process will execute that code.

PoC

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

var payload = '---javascript\n((require("child_process")).execSync("calc.exe"))\n---RCE';

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

Running the PoC on Windows launches the calculator application, demonstrating arbitrary code execution.

• Remote code execution in the process that performs Markdown->PDF conversion.
• If the converter is run in a web app or cloud service, an attacker uploading malicious Markdown can execute arbitrary commands on the

Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.

CVE-2025-65108 has a CVSS score of 10.0 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.2.5); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-65108? CVE-2025-65108 is a critical-severity code injection vulnerability in md-to-pdf (npm), affecting versions < 5.2.5. It is fixed in 5.2.5. Untrusted input is evaluated as executable code within the application's runtime environment.
2. How severe is CVE-2025-65108? CVE-2025-65108 has a CVSS score of 10.0 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of md-to-pdf are affected by CVE-2025-65108? md-to-pdf (npm) versions < 5.2.5 is affected.
4. Is there a fix for CVE-2025-65108? Yes. CVE-2025-65108 is fixed in 5.2.5. Upgrade to this version or later.
5. Is CVE-2025-65108 exploitable, and should I be worried? Whether CVE-2025-65108 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-65108 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-65108? Upgrade md-to-pdf to 5.2.5 or later.