CVE-2025-65026 MEDIUM

CVE-2025-65026: esm.sh CDN service has JS Template Literal Injection in CSS-to-JavaScript

Vendor Esm-Dev
Product esm.sh
Weakness CWE-94 · Code injection
Published November 19, 2025
Last update November 20, 2025

CVSS base score

6.1/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality Low
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

What the vulnerability does

Description

esm.sh is a nobuild content delivery network(CDN) for modern web development. Prior to version 136, The esm.sh CDN service contains a Template Literal Injection vulnerability (CWE-94) in its CSS-to-JavaScript module conversion feature. When a CSS file is requested with the ?module query parameter, esm.sh converts it to a JavaScript module by embedding the CSS content directly into a template literal without proper sanitization. An attacker can inject malicious JavaScript code using ${...} expressions within CSS files, which will execute when the module is imported by victim applications. This enables Cross-Site Scripting (XSS) in browsers and Remote Code Execution (RCE) in Electron applications. This issue has been patched in version 136.

Key dates

Disclosure timeline

November 19, 2025 CVE published
November 20, 2025 Record updated