CVE Explorer
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 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.
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"product":"esm.sh","vendor":"esm-dev","versions":[{"status":"affected","version":"<= 137"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:61e0517f5f92f8fa05d9bd1e04fac8d41d2805706844881792b801f8e3097fb2 · sha256:a1e3043efb303b9c… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":8.6,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","version":"3.0"},"metric_type":"cvssV3_0"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:61e0517f5f92f8fa05d9bd1e04fac8d41d2805706844881792b801f8e3097fb2 · sha256:a1e3043efb303b9c… · /containers/cna/metrics/0/cvssV3_0
CWE assertions
1 source assertion{"cweId":"CWE-918","description":"CWE-918: Server-Side Request Forgery (SSRF)","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:61e0517f5f92f8fa05d9bd1e04fac8d41d2805706844881792b801f8e3097fb2 · sha256:a1e3043efb303b9c… · /containers/cna/problemTypes/0/descriptions/0
Source references
1 source assertion{"name":"https://github.com/esm-dev/esm.sh/security/advisories/GHSA-p2v6-84h2-5x4r","tags":["x_refsource_CONFIRM"],"url":"https://github.com/esm-dev/esm.sh/security/advisories/GHSA-p2v6-84h2-5x4r"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:61e0517f5f92f8fa05d9bd1e04fac8d41d2805706844881792b801f8e3097fb2 · sha256:a1e3043efb303b9c… · /containers/cna/references/0
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.