CVE-2026-27730

7.5 HIGH
Published: February 25, 2026 Modified: February 27, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/esm-dev/esm.sh/security/advisories/GHSA-p2v6-84h2-5x4r
Source: security-advisories@github.com
Exploit Vendor Advisory

1 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.5 / 10.0
EPSS (Exploit Probability)
0.0%
12th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

esm