Path Traversal in Esm Esm.sh
CVE-2026-23644
esm.sh is a no-build content delivery network (CDN) for web development. Prior to Go pseeudoversion 0.0.0-20260116051925-c62ab83c589e, the software has a path traversal vulnerability due to an incomplete fix. `path.Clean` normalizes a path but does not prevent absolute paths in a malicious tar file. Commit https://github.com/esm-dev/esm.sh/commit/9d77b88c320733ff6689d938d85d246a3af9af16, corresponding to pseudoversion 0.0.0-20260116051925-c62ab83c589e, fixes this issue.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.005 (43.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 43.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.001
Affected products
- Esm Esm.sh
- Esm-Dev Esm.sh — versions < 0.0.0-20260116051925-c62ab83c589e
Weakness classification (CWE)
References
- github.com/esm-dev/esm.sh/security/advisories/GHSA-2657-3c98-63jq (Vendor Advisory)
- github.com/esm-dev/esm.sh/commit/9d77b88c320733ff6689d938d85d246a3af9af16 (Patch)
- github.com/esm-dev/esm.sh/commit/c62ab83c589e7b421a0e1376d2a00a4e48161093 (Patch)
- pkg.go.dev/vuln/GO-2025-4138 (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-23644?
- CVE-2026-23644 is a high-severity vulnerability in Esm Esm.sh, classified under Path Traversal. CVSS score: 7.5/10. Published 2026-01-18.
- How severe is CVE-2026-23644?
- High severity. CVSS v3 base score is 7.5 out of 10.