CVE-2026-44594

esm.sh: Path Traversal via package.json browser field allows reading arbitrary server files

State: Published
Severity: 7.5 High
Published: May 28, 2026
Updated: May 28, 2026
Reserved: May 6, 2026

Description

esm.sh is a no-build content delivery network (CDN) for web development. In 137 and earlier, a Local File Inclusion (LFI) vulnerability exists in the esbuild plugin's handling of the browser field in package.json. An attacker can publish an npm package that causes the server to read and return arbitrary files from the host filesystem during the build process.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	GitHub_M

Weaknesses

CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Affected Products

Product	Versions
esm.shesm-dev	<= 137Affected

References

https://github.com/esm-dev/esm.sh/security/advisories/GHSA-rg65-45m7-hq57

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