ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2026-27730

esm.sh is a no-build content delivery network (CDN) for web development.

Published Feb 25, 2026 · catalog updated Jun 17, 2026 · esm.sh is a no-build

Check if you run it

No confirmed exploitation is on record for CVE-2026-27730. EPSS is 0.48%. Act only if a listed version of esm.sh is a no-build is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (esm.sh is a no-build).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.48%
Remediation
Advisory link
Affected products
cpe esm/esm.sh

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 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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe esm/esm.shversion unspecified

How to fix CVE-2026-27730

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-27730. EPSS is 0.48%. Act only if a listed version of esm.sh is a no-build is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-918: Server-Side Request Forgery (SSRF). EPSS 0.48%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 25, 2026 · NIST NVD

    Detected

    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 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 loc

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 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 loc

Sources

  • CVE.orgVulnerability recordCVE-2026-27730

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-27730

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-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 fetch route. The service tries to block localhost/internal targets, but the validation is based on hostname string

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.