CVE-2025-65026

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.

CVSS 3.1

9.6CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

EPSS

0.5% chance of exploitation in the next 30 days; higher than 43% of CVEs (scores of 2026-10-25)

CWEs

CWE-79, CWE-94

Published

2025-11-19

Modified

2026-10-18

Record from

the NVD, synced 2026-10-19

Affected

• esm:esm.sh

Packages (OSV)

References

• https://github.com/esm-dev/esm.sh/commit/87d2f6497574bf4448641a5527a3ac2beba5fd6c
• https://github.com/esm-dev/esm.sh/security/advisories/GHSA-hcpf-qv9m-vfgp
• https://github.com/esm-dev/esm.sh/security/advisories/GHSA-hcpf-qv9m-vfgp

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