CVEvulnerability

CVE-2026-27730

7.5 HIGH Published 2026-02-25 Modified 2026-06-17 Official page ↗
Status
Analyzed
Published
2026-02-25
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS 3.0 ([email protected])
8.6 HIGH — CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Weaknesses
CWE-918

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.

Affected configurations

• esm esm.sh (<= 137)

Related

Weakness · CWE (1)

  • CWE-918 Server-Side Request Forgery weakness

References