TI-2026-32505 Aliases CVE-2026-44594 GHSA-rg65-45m7-hq57

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

HIGH 72CWE-22Published 2026-05-28 · Updated 2026-05-28

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Information disclosure
Confidentiality · integrity · availability: High · None · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-22 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00387 33rd percentileScored 2026-11-07

Fix Fixed github.com/esm-dev/esm.sh (Go): 0.0.0-20250616164159-0593516c4cfa

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
esm-dev	esm.sh	up to 137	—	No fix listed	CNA
—	github.com/esm-dev/esm.sh (Go)	before 0.0.0-20250616164159-0593516c4cfa	0.0.0-20250616164159-0593516c4cfa	Patch available	GHSA-rg65-45m7-hq57

esm.sh Vendoresm-dev Affected up to 137 Fixed in — No fix listed CNA
github.com/esm-dev/esm.sh (Go) Vendor— Affected before 0.0.0-20250616164159-0593516c4cfa Fixed in 0.0.0-20250616164159-0593516c4cfa Patch available GHSA-rg65-45m7-hq57

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:esm:esm.sh::::::::	—	—	esm-dev

cpe:2.3:a:esm:esm.sh:*:*:*:*:*:*:*:* Versions — — ·esm-dev

Remediation

Fix · GHSA-rg65-45m7-hq57 github.com/esm-dev/esm.sh (Go) Fixed in 0.0.0-20250616164159-0593516c4cfa Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-44594
2026-10-03 Alias added: GHSA-rg65-45m7-hq57

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-44594

Other 3

TI-2025-40211 esm.sh CDN service has arbitrary file write via tarslip CVSS 3.1CRITICAL 9.8
TI-2026-32504 esm.sh: Legacy Route Path Traversal Can Lead to RCE CVSS 4.0HIGH 8.7
TI-2025-32063 esm.sh is vulnerable to full-response SSRF CVSS 4.0HIGH 8.7
TI-2025-40212 esm.sh CDN service has JS Template Literal Injection in CSS-to-JavaScript CVSS 3.1CRITICAL 9.6
TI-2025-36902 Local File Inclusion in esm.sh CVSS 4.0HIGH 7.7
TI-2026-22092 esm.sh has SSRF localhost/private-network bypass in `/http(s)` module route CVSS 3.1HIGH 7.5

See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences