CVE-2026-44593 — esm.sh: Legacy Route Path Traversal Can Lead to RCE
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 …
Published: 2026-05-28 · CVSS: 8.7 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7