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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| esm-dev | esm.sh | <= 137 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 | openSUSE-SU-2026:21483-1 |
| openSUSE Leap 15.6 | govulncheck-vulndb | 0.0.20260317T205859-150000.1.152.1 | SUSE-SU-2026:1042-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/esm-dev/esm.sh | < 0.0.0-20250616164159-0593516c4cfa | 0.0.0-20250616164159-0593516c4cfa | GHSA-p2v6-84h2-5x4r |
Advisories 2
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026
- SUSE-SU-2026:1042-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Mar 26, 2026