CVE-2026-27730

🔴 HIGH

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...

Published
Feb 25, 2026
Last Modified
Feb 27, 2026
Views
4
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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 Products (1)

esm - esm.sh

Version: *

CVSS Scores

CVSS 3.1 7.5
7.5
HIGH
CVSS 2.0 7.5

References

Additional Information

Source
security-advisories@github.com
State
Analyzed

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