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CVE-2026-27730

nvd nist
Published: Feb 25, 2026Modified: Feb 27, 2026

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7.5
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Exploitability: 3.9 / Impact: 3.6
Source: 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.

Affected (1)

Products: Esm: Esm.sh
Esm
1 product
Esm.sh
Configuration A
1 vulnerable
Vulnerable SoftwareAffected Versions
Esm.sh
Up to 137

Related CWEs

CWE-918
Server-Side Request Forgery (SSRF)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

References (1)

Source: security-advisories@github.com
ExploitVendor Advisory

Timeline

No history available yet.