Vulnerability in Esm-Dev Esm.sh

CVE-2025-59342

esm.sh is a nobuild content delivery network(CDN) for modern web development. In 136 and earlier, a path-traversal flaw in the handling of the X-Zone-Id HTTP header allows an attacker to cause the application to write files outside the intended storage location. The header value is used to build a filesystem path but is not properly canonicalized or restricted to the application’s storage base directory. As a result, supplying ../ sequences in X-Zone-Id causes files to be written to arbitrary directories. Version 136.1 contains a patch.

Published · last modified .

EPSS exploit prediction

EPSS: 0.030 (87.0th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 87th percentile — 87.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-59342: held from 0.030 to 0.030.

EPSS over last 30 days · oldest: 0.030 · newest: 0.030 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-59342?
CVE-2025-59342 is a vulnerability in Esm-Dev Esm.sh, classified under CWE-24. Published 2025-09-17.
Is CVE-2025-59342 known to be exploited?
4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.