Описание
esm.sh has File Inclusion issue
Summary
A Local File Inclusion (LFI) issue was identified in the esm.sh service URL handling. An attacker could craft a request that causes the server to read and return files from the host filesystem (or other unintended file sources).
Severity: High — LFI can expose secrets, configuration files, credentials, or enable further compromise. Impact: reading configuration files, private keys, environment files, or other sensitive files; disclosure of secrets or credentials; information leakage that could enable further attacks.
Vulnerable code snippet is in this file: https://github.com/esm-dev/esm.sh/blob/c62f191d32639314ff0525d1c3c0e19ea2b16143/server/router.go#L1168
Proof of Concept
- Using this default config file that I copy from the repo, the server is running at
http://localhost:9999with this commandgo run server/esmd/main.go --config=config.json
- Trigger the LFI vulnerability by sending this command below to read a local file
Remediation
Simply remove any .. in the URL path before actually process the file. See more details in this guide
Credits
Ссылки
- https://github.com/esm-dev/esm.sh/security/advisories/GHSA-49pv-gwxp-532r
- https://nvd.nist.gov/vuln/detail/CVE-2025-59341
- https://github.com/esm-dev/esm.sh/commit/492de92850dd4d350c8b299af541f87541e58a45
- https://github.com/esm-dev/esm.sh/blob/c62f191d32639314ff0525d1c3c0e19ea2b16143/server/router.go#L1168
- https://pkg.go.dev/vuln/GO-2025-3962
Пакеты
github.com/esm-dev/esm.sh
<= 136
Отсутствует
Связанные уязвимости
esm.sh is a nobuild content delivery network(CDN) for modern web development. In 136 and earlier, a Local File Inclusion (LFI) issue was identified in the esm.sh service URL handling. An attacker could craft a request that causes the server to read and return files from the host filesystem (or other unintended file sources).