CVE-2026-27730

HIGH EPSS 25.8%
Published Feb 25, 20264mo ago · Modified Jun 17, 20262w ago
7.5 CVSS 3.1
High
Find Similar
Published Feb 25, 2026 4mo ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
7.5
Exploitability
3.9
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity None
Availability None

Threat Intelligence

EPSS Exploit Probability
25.8% percentile
Exploit & Patch Status
Public Exploit Known
No Patch Available

Weaknesses 1

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

Affected Products 1

VendorProductVersionRange
esmesm.sh* ≤137

References 1

  • github.com https://github.com/esm-dev/esm.sh/security/advisories/GHSA-p2v6-84h2-5x4r
    ExploitVendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.