CVE-2026-44593

published 2026-05-28

CVE-2026-44593: 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…

Priority P3 54 high 8.7 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 E X CR X IR X AR X MAV X MAC X MAT X MPR X MUI X MVC X MVI X MVA X MSC X MSI X MSA X S X AU X R X V X RE X U X

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.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
esm-dev	esm.sh	<= 137	—
github.com	esm-dev_esm.sh	>= 0 < 0.0.0-20260508100112-1960055e1d53	0.0.0-20260508100112-1960055e1d53

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CWE-22