Fix OS command and argument injection in Node.js and Express
============================================================

Run the program directly with its arguments as a list - execFileSync(tool,
['--', name]) - so no shell parses them, and put '--' before any user operand
so a leading dash cannot pose as an option. Never build a string for
child_process.exec/execSync. Choose a format from an allowlist, never from
free text.

Page: https://softwaresecurity.com/fix/command-injection/node-express/

What is in this archive
-----------------------
command-injection/node-express/   the project: three implementations of the same code and one test suite
  impl/vulnerable.js   (vulnerable)
  impl/fixed.js   (fixed)
  impl/wrong.js   (a plausible fix that still fails)
run-all.mjs   runs the tests in all three modes and checks the results (Node.js only)
LICENSE-CODE.txt

Run it
------
  Tested with Node.js 26.11.1 (node:child_process is built in); package.json
  allows Node.js ^22.23.2 || ^24.18.1 || >=26.5.1. run-all.mjs needs Node.js 22
  or later. Supported versions: https://softwaresecurity.com/fix/versions/

  From the command-injection/node-express folder, install the dependencies once
  (this needs network access):

    npm ci

  Then run the tests. IMPL chooses the implementation the tests load:

    # every test passes
    IMPL=fixed npm test --silent
    # an exploit test fails
    IMPL=vulnerable npm test --silent
    # a test fails
    IMPL=wrong npm test --silent

  The JUnit report is written to reports/junit.xml. To run all three modes and
  check the results in one step, run the harness from this top folder (it needs
  only Node.js; --install runs the install step first):

    node run-all.mjs --install command-injection/node-express
    node run-all.mjs command-injection/node-express

Verified
--------
  11 October 2026 on macOS 27.0 (Darwin 27.0.0, arm64), with node 26.11.1,
  express 5.3.0, shell /bin/sh (dash-compatible POSIX shell). Versions and
  results hold for that date: run the tests with your own versions before
  relying on the fix.

Licence
-------
  The code is MIT licensed (LICENSE-CODE.txt). The page text is CC BY 4.0.
