High severity · published Jan 18, 2026
CVE-2026-23644
esm.sh has path traversal in `extractPackageTarball` that enables file writes from malicious packages
7.5
CVSS
0.6%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 46% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ES
esm.sh · esm-dev
< 0.0.0-20260116051925-c62ab83c589e · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-23644
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-23644
Patch
https://github.com/esm-dev/esm.sh/commit/9d77b88c320733ff6689d938d85d246a3af9af16
Patch
https://github.com/esm-dev/esm.sh/commit/c62ab83c589e7b421a0e1376d2a00a4e48161093
Vendor Advisory
https://github.com/esm-dev/esm.sh/security/advisories/GHSA-2657-3c98-63jq
Exploit
https://pkg.go.dev/vuln/GO-2025-4138
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