Description
esm.sh is a no-build content delivery network (CDN) for web development. In 137 and earlier, the legacy router first retrieves a response from legacyServer, parses the incoming request path, and ultimately writes the data to storage via buildStorage.Put. The router concatenates the path components without sanitizing them, producing a storage key. When this key is used, the underlying file system resolves the relative segments and writes the file to the specified path. Thus an attacker can craft a request that writes data to arbitrary locations on the server.
Published: 2026-05-28
Score: 8.7 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-3636-h3vx-6465 esm.sh: Legacy Route Path Traversal Can Lead to RCE
History

Tue, 02 Jun 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sat, 30 May 2026 21:15:00 +0000

Type Values Removed Values Added
First Time appeared Esm-dev
Esm-dev esmsh
Vendors & Products Esm-dev
Esm-dev esmsh

Thu, 28 May 2026 15:30:00 +0000

Type Values Removed Values Added
Description esm.sh is a no-build content delivery network (CDN) for web development. In 137 and earlier, the legacy router first retrieves a response from legacyServer, parses the incoming request path, and ultimately writes the data to storage via buildStorage.Put. The router concatenates the path components without sanitizing them, producing a storage key. When this key is used, the underlying file system resolves the relative segments and writes the file to the specified path. Thus an attacker can craft a request that writes data to arbitrary locations on the server.
Title esm.sh: Legacy Route Path Traversal Can Lead to RCE
Weaknesses CWE-22
References
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-02T15:01:05.268Z

Reserved: 2026-05-06T21:49:12.425Z

Link: CVE-2026-44593

cve-icon Vulnrichment

Updated: 2026-06-02T14:59:45.872Z

cve-icon NVD

Status : Deferred

Published: 2026-05-28T16:16:24.587

Modified: 2026-06-02T16:16:41.203

Link: CVE-2026-44593

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-30T21:00:12Z

Weaknesses