CVE-2025-59342Public exploitNetwork attack vector

Arbitrary file write via unchecked zone identifier

Published Sep 17, 2025 · Updated Sep 17, 2025

Path traversal in the POST /transform endpoint of esm-dev esm.sh 136 and earlier allows remote attackers to write arbitrary files. The router passes the X-Zone-Id header into normalizeSavePath without validating it as a domain or constraining the resolved path to storage. An unauthenticated HTTP request containing ../ sequences can create or overwrite files writable by the server process outside its storage directory.

CVSS severityUnavailable
Unscored
EPSS probability3.03%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Path traversal in the POST /transform endpoint of esm-dev esm.sh 136 and earlier allows remote attackers to write arbitrary files. The router passes the X-Zone-Id header into normalizeSavePath without validating it as a domain or constraining the resolved path to storage. An unauthenticated HTTP request containing ../ sequences can create or overwrite files writable by the server process outside its storage directory.

The record

CVE
CVE-2025-59342
Published
Sep 17, 2025
Updated
Sep 17, 2025
Vendor
esm-dev
Product
esm.sh
Classifications
CWE-24, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 17, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 136

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

esm-dev · esm.shversion=<= 136

Published CVSS scores

5.5GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-24Path Traversal: '../filedir'
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo