CVE-2026-27730
Last modified
CVE-2026-27730 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.34% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Esm | Esm.Sh | <= 137 |
References
- https://github.com/esm-dev/esm.sh/security/advisories/GHSA-p2v6-84h2-5x4rExploit, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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