🛡️ CVE-2026-27730
🟠 CVSS 8.0 — High ⚠️ Exploit Public CWE-918 NVD
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

esm.sh is a no-build content delivery network (CDN) for web development. Versions up to and including 137 have an SSRF vulnerability (CWE-918) in esm.sh’s `/http(s)` fetch route. The service tries to block localhost/internal targets, but the validation is based on hostname string checks and can be bypassed using DNS alias domains. This allows an external requester to make the esm.sh server fetch internal localhost services. As of time of publication, no known patched versions exist.

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE CWE-918
Public Exploit ⚠️ Yes
Source NVD
Published 2026-02-25
Updated 2026-06-15
Modified 2026-02-27
Fix URL N/A

Affected Packages

Software From version Fixed in
esm.sh — 137
github.com/esm-dev/esm.sh — —

Similar Threats

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