Moderate severity vulnerabilities found after running npx create-react-app

Question

I have installed the latest LTS Version: 14.17.0 (includes npm 6.14.13) of 32-bit on Windows. After the node installation, I've installed create-react-app module globally using npm i create-react-app -g

I've installed both of them successfully without any errors. But, if I try to run npx create-react-app <project-name> on my terminal, I get 82 moderate severity vulnerabilities of browserslist and postcss dependencies saying Regular Expression Denial of Service I've also tried using the older versions of node but, the vulnerabilities are still the same.

The vulnerabilities gets fixed after including "preinstall": "npx npm-force-resolutions" in the scripts and "resolutions": "^3.8.0" in my package.json file. But, I would to do this every time I create a new project.

Please suggest me a permanent fix to this.

I am also including the vulnerabilities using npm audit

# npm audit report

browserslist  4.0.0 - 4.16.4
Severity: moderate
Regular Expression Denial of Service - https://npmjs.com/advisories/1747
fix available via `npm audit fix --force`
Will install [email protected], which is a breaking change
node_modules/react-dev-utils/node_modules/browserslist
  react-dev-utils  >=6.0.0-next.03604a46
  Depends on vulnerable versions of browserslist
  node_modules/react-dev-utils
    react-scripts  >=2.0.0-next.03604a46
    Depends on vulnerable versions of postcss-normalize
    Depends on vulnerable versions of react-dev-utils
    Depends on vulnerable versions of resolve-url-loader
    node_modules/react-scripts

postcss  7.0.0 - 8.2.9
Severity: moderate
Regular Expression Denial of Service - https://npmjs.com/advisories/1693
fix available via `npm audit fix --force`
Will install [email protected], which is a breaking change
node_modules/postcss
node_modules/resolve-url-loader/node_modules/postcss
  autoprefixer  9.0.0 - 9.8.6
  Depends on vulnerable versions of postcss
  node_modules/autoprefixer
  css-blank-pseudo  *
  Depends on vulnerable versions of postcss
  node_modules/css-blank-pseudo
    postcss-preset-env  >=6.0.0
    Depends on vulnerable versions of css-blank-pseudo
    Depends on vulnerable versions of css-prefers-color-scheme
    Depends on vulnerable versions of postcss
    Depends on vulnerable versions of postcss-color-gray
    Depends on vulnerable versions of postcss-double-position-gradients
    node_modules/postcss-preset-env
  css-declaration-sorter  4.0.0 - 5.1.2
  Depends on vulnerable versions of postcss
  node_modules/css-declaration-sorter
  css-has-pseudo  *
  Depends on vulnerable versions of postcss
  node_modules/css-has-pseudo
  css-loader  2.0.0 - 4.3.0
  Depends on vulnerable versions of postcss
  node_modules/css-loader
  css-prefers-color-scheme  *
  Depends on vulnerable versions of postcss
  node_modules/css-prefers-color-scheme
  cssnano  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.1.1 - 4.1.11
  Depends on vulnerable versions of postcss
  node_modules/cssnano
    optimize-css-assets-webpack-plugin  3.2.1 || 5.0.2 - 5.0.6
    Depends on vulnerable versions of cssnano
    node_modules/optimize-css-assets-webpack-plugin
  cssnano-preset-default  <=4.0.0-rc.2 || 4.0.1 - 4.0.8
  Depends on vulnerable versions of cssnano-util-raw-cache
  Depends on vulnerable versions of postcss
  Depends on vulnerable versions of postcss-calc
  node_modules/cssnano-preset-default
  cssnano-util-raw-cache  >=4.0.1
  Depends on vulnerable versions of postcss
  node_modules/cssnano-util-raw-cache
  icss-utils  4.0.0 - 4.1.1
  Depends on vulnerable versions of postcss
  node_modules/icss-utils
    postcss-modules-local-by-default  2.0.0 - 4.0.0-rc.4
    Depends on vulnerable versions of icss-utils
    Depends on vulnerable versions of postcss
    node_modules/postcss-modules-local-by-default
    postcss-modules-values  2.0.0 - 4.0.0-rc.5
    Depends on vulnerable versions of icss-utils
    Depends on vulnerable versions of postcss
    node_modules/postcss-modules-values
  postcss-attribute-case-insensitive  4.0.0 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-attribute-case-insensitive
  postcss-browser-comments  2.0.0 - 3.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-browser-comments
    postcss-normalize  7.0.0 - 9.0.0
    Depends on vulnerable versions of postcss
    Depends on vulnerable versions of postcss-browser-comments
    node_modules/postcss-normalize
      react-scripts  >=2.0.0-next.03604a46
      Depends on vulnerable versions of postcss-normalize
      Depends on vulnerable versions of react-dev-utils
      Depends on vulnerable versions of resolve-url-loader
      node_modules/react-scripts
  postcss-calc  6.0.2 - 7.0.5
  Depends on vulnerable versions of postcss
  node_modules/postcss-calc
  postcss-color-functional-notation  >=2.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-color-functional-notation
  postcss-color-gray  >=5.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-color-gray
  postcss-color-hex-alpha  4.0.0 - 6.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-color-hex-alpha
  postcss-color-mod-function  >=3.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-color-mod-function
  postcss-color-rebeccapurple  >=4.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-color-rebeccapurple
  postcss-colormin  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.2 - 4.0.3
  Depends on vulnerable versions of postcss
  node_modules/postcss-colormin
  postcss-convert-values  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-convert-values
  postcss-custom-media  7.0.0 - 7.0.8
  Depends on vulnerable versions of postcss
  node_modules/postcss-custom-media
  postcss-custom-properties  8.0.0 - 10.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-custom-properties
  postcss-custom-selectors  5.0.0 - 5.1.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-custom-selectors
  postcss-dir-pseudo-class  >=5.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-dir-pseudo-class
  postcss-discard-comments  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-discard-comments
  postcss-discard-duplicates  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-discard-duplicates
  postcss-discard-empty  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-discard-empty
  postcss-discard-overridden  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-discard-overridden
  postcss-double-position-gradients  *
  Depends on vulnerable versions of postcss
  node_modules/postcss-double-position-gradients
  postcss-env-function  >=2.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-env-function
  postcss-flexbugs-fixes  4.0.0 - 4.2.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-flexbugs-fixes
  postcss-focus-visible  >=4.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-focus-visible
  postcss-focus-within  >=3.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-focus-within
  postcss-font-variant  4.0.0 - 4.0.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-font-variant
  postcss-gap-properties  >=2.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-gap-properties
  postcss-image-set-function  >=3.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-image-set-function
  postcss-initial  3.0.0 - 3.0.4
  Depends on vulnerable versions of postcss
  node_modules/postcss-initial
  postcss-lab-function  >=2.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-lab-function
  postcss-loader  3.0.0 - 4.0.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-loader
  postcss-logical  >=2.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-logical
  postcss-media-minmax  4.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-media-minmax
  postcss-merge-longhand  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.6 - 4.0.11
  Depends on vulnerable versions of postcss
  node_modules/postcss-merge-longhand
  postcss-merge-rules  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.2 - 4.0.3
  Depends on vulnerable versions of postcss
  node_modules/postcss-merge-rules
  postcss-minify-font-values  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-minify-font-values
  postcss-minify-gradients  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-minify-gradients
  postcss-minify-params  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-minify-params
  postcss-minify-selectors  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-minify-selectors
  postcss-modules-extract-imports  2.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-modules-extract-imports
  postcss-modules-scope  2.0.0 - 2.2.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-modules-scope
  postcss-nesting  7.0.0 - 7.0.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-nesting
  postcss-normalize-charset  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-normalize-charset
  postcss-normalize-display-values  <=4.0.0-rc.2 || 4.0.1 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-normalize-display-values
  postcss-normalize-positions  <=4.0.0-rc.2 || 4.0.1 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-normalize-positions
  postcss-normalize-repeat-style  <=4.0.0-rc.2 || 4.0.1 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-normalize-repeat-style
  postcss-normalize-string  <=4.0.0-rc.2 || 4.0.1 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-normalize-string
  postcss-normalize-timing-functions  <=4.0.0-rc.2 || 4.0.1 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-normalize-timing-functions
  postcss-normalize-unicode  <=4.0.0-rc.2 || 4.0.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-normalize-unicode
  postcss-normalize-url  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-normalize-url
  postcss-normalize-whitespace  <=4.0.0-rc.2 || 4.0.1 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-normalize-whitespace
  postcss-ordered-values  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.1.1 - 4.1.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-ordered-values
  postcss-overflow-shorthand  >=2.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-overflow-shorthand
  postcss-page-break  2.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-page-break
  postcss-place  >=4.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-place
  postcss-pseudo-class-any-link  >=6.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-pseudo-class-any-link
  postcss-reduce-initial  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.2 - 4.0.3
  Depends on vulnerable versions of postcss
  node_modules/postcss-reduce-initial
  postcss-reduce-transforms  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.2
  Depends on vulnerable versions of postcss
  node_modules/postcss-reduce-transforms
  postcss-replace-overflow-wrap  3.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-replace-overflow-wrap
  postcss-selector-matches  >=4.0.0
  Depends on vulnerable versions of postcss
  node_modules/postcss-selector-matches
  postcss-selector-not  4.0.0 - 4.0.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-selector-not
  postcss-svgo  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.3
  Depends on vulnerable versions of postcss
  node_modules/postcss-svgo
  postcss-unique-selectors  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1
  Depends on vulnerable versions of postcss
  node_modules/postcss-unique-selectors
  resolve-url-loader  3.0.0-alpha.1 - 4.0.0
  Depends on vulnerable versions of postcss
  node_modules/resolve-url-loader
  stylehacks  4.0.0-nightly.2020.1.9 - 4.0.0-rc.2 || 4.0.1 - 4.0.3
  Depends on vulnerable versions of postcss
  node_modules/stylehacks

82 moderate severity vulnerabilities

To address issues that do not require attention, run:
  npm audit fix

To address all issues (including breaking changes), run:
  npm audit fix --force ```

Chile

The React team would need to fix those issues. It happens because the packages required by a new project with create-react-app have vulnerabilities. Developers don't care about warnings (disclaimer: you should care about warnings, but sometimes it's ok to ignore them) – Dick

Answer 1

A crude way to temporarily (hopefully) fix this is to add it to dependencies and resolutions.

Adding it to resolutions will stop the dependency of react-scripts from being installed altogether (intentionally causing the module not found error).

Adding it to dependencies will install the updated version.

It will then find and use the installed dependency (updated version) as the dependency of react-scripts on build.

"dependencies": {
    "browserslist": "^4.16.5",
}
"resolutions": {
    "browserslist": "4.16.5"
}

Hanley

Answer 2

Until react-scripts is updated by the CRA team I think for npx npm-force-resolutions to work you might need to edit your package.json and add a "resolutions" section at the root. Inside this section you can then try specifying the version updates for the problem packages. So for your postcss it would look like the following (changing the versions to those suggested as fixes by npm audit):

  "resolutions": {
    "postcss": "7.0.36",
    "glob-parent": "^5.1.2",
    "css-what": "^5.0.1",
    "normalize-url": "^4.5.1"
  }

The above config is how I seemed to have solved my CRA project reporting 8 vulnerabilities with 4 moderate and 4 High down to one moderate vulnerability regarding the browserslist package. Version 7.0.36 of postcss is the latest version 7 postcss that has had the ReDoS fix backported from postcss version 8. I tried updating postcss to 8 in resolutions but it causes other issues which, I'm guessing, relate to breaking changes for postcss plugins used in WebPack. I'm a web dev newcomer so I'm guessing here. Finally, I cannot seem to update browserlist without it causing 'browserlist module not found' errors at runtime when executing npm start.

Here's my terminal output with everything in place and running npm i

  npm i

> [email protected] preinstall F:\01-Projects\testpostcss
> npx npm-force-resolutions

npx: installed 6 in 1.566s
npm WARN @babel/[email protected] requires a peer of @babel/core@^7.13.0 but none is installed. You must install peer dependencies yourself.    
npm WARN [email protected] requires a peer of typescript@>=2.8.0 || >= 3.2.0-dev || >= 3.3.0-dev || >= 3.4.0-dev || >= 3.5.0-dev || >= 3.6.0-dev || >= 3.6.0-beta || >= 3.7.0-dev || >= 3.7.0-beta but none is installed. You must install peer dependencies yourself.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: [email protected] (node_modules\watchpack-chokidar2\node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for [email protected]: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: [email protected] (node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for [email protected]: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"}) 
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: [email protected] (node_modules\webpack-dev-server\node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for [email protected]: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})

audited 2422 packages in 17.483s

141 packages are looking for funding
  run `npm fund` for details

found 1 moderate severity vulnerability
  run `npm audit fix` to fix them, or `npm audit` for details
  seefe   testpostcss  master ≢  ~2   14.17.1  ﮫ 18.808s 
   npm audit

                       === npm audit security report ===                        


                                 Manual Review                                  
             Some vulnerabilities require your attention to resolve             
                                                                                
          Visit https://go.npm.me/audit-guide for additional guidance           


  Moderate        Regular Expression Denial of Service                          

  Package         browserslist                                                  

  Patched in      >=4.16.5                                                      

  Dependency of   react-scripts                                                 

  Path            react-scripts > react-dev-utils > browserslist                

  More info       https://npmjs.com/advisories/1747                             

found 1 moderate severity vulnerability in 2422 scanned packages
  1 vulnerability requires manual review. See the full report for details.
  seefe   testpostcss  master ≢  ~2   14.17.1  ﮫ 2.442s   

Precancel

Answer 3

i faced this annoying error so many times and this is how i fixed the error,

first run npm audit

then most of the times it asks me: npm ERR ! audit Try creating one first with: npm i --package-lock-only

then i type npm i --package-lock-only

and most the times it works, there are no more vulnerabilities.

The error happens but i don't know what really cause it. The solution i provided works for me and there are no more vulnerabilities.

Here is an image showing the error happening [1]: https://i.sstatic.net/JMED4.jpg

here is an image showing the solution that i used. [2]: https://i.sstatic.net/DQFUV.jpg

Wieland

give me your feedback about this solution – Wieland

Please provide additional details in your answer. As it's currently written, it's hard to understand your solution. – Hydrous

I am going to add the image links to the issue in the new answer. – Wieland