CVE-2026-44593

critical

Published 2026-05-12 · Modified 2026-05-28

CVSS v4

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

CVSS v3

—

VIR risk

9.5

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.

Predictions

Exploit likelihood

20%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No vendor mitigations ingested yet for this CVE. The mitigation-content worker queues fetches as references arrive — check back in a few minutes, or see the references list below.

Package impact

Ecosystem	Package	Vulnerable	Fixed
Go	github.com/esm-dev/esm.sh	`<0.0.0-20260508100112-1960055e1d53`	`0.0.0-20260508100112-1960055e1d53`
GO	github.com/esm-dev/esm.sh	`< 0.0.0-20260508100112-1960055e1d53`	`0.0.0-20260508100112-1960055e1d53`

References

CWEs

CWE-22

💬 Discuss CVE-2026-44593 on VIR Community →

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.