What is CVE-2026-27730?

CVE-2026-27730 is a high-severity vulnerability in Esm-dev Esm.sh, classified under Server-Side Request Forgery (SSRF). CVSS score: 8.6/10. Published 2026-02-25.

How severe is CVE-2026-27730?

High severity. CVSS v3 base score is 8.6 out of 10.

SSRF in Esm-dev Esm.sh

CVE-2026-27730

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 t…

Vulnerability class: SSRF (Server-Side Request Forgery)

EPSS: 0.001 (20.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.6 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N.

Affected products

Esm-dev Esm.sh — versions <= 137

Weakness classification (CWE)

CWE-918 — Server-Side Request Forgery (SSRF)

References

https://github.com/esm-dev/esm.sh/security/advisories/GHSA-p2v6-84h2-5x4r (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-27730?: CVE-2026-27730 is a high-severity vulnerability in Esm-dev Esm.sh, classified under Server-Side Request Forgery (SSRF). CVSS score: 8.6/10. Published 2026-02-25.
How severe is CVE-2026-27730?: High severity. CVSS v3 base score is 8.6 out of 10.