postcss 7.0.0 - 8.2.9 Severity: moderate Regular Expression Denial of Service

user_11895568 0
Viewed 10622

When creating a new project under create-react-app, you get warnings straight away regarding a vulnerability found in postcss.

Issue reported by npm: https://www.npmjs.com/advisories/1693

Related open issues can be found here:

The issue has been patched on postcss v8.2.10, but it's still present when creating new projects as react-scripts hasn't upgraded the dependency yet.

So, my problem here is I can no longer run builds as they fail due to the vulnerability.

Since I can't wait for them to get it patched before to keep working on my stuff (they seem to be aware of it since a year ago), is there some workaround that could be applied to solve it?

I tried adding a postcss resolution on package.json:

  "resolutions": {
    "postcss": "^8.2.10"
  },

but that didn't land me far.

Any idea?

react-scripts postcss create-react-app reactjs
4 Answers
user_159061830

Switching to Yarn makes this far simpler.

rm -rf ./node_modules 
rm ./package-lock.json

edit your package.json :
add any other package versions to upgrade from npm / yarn audit here also

  "resolutions": 
  {
    "postcss": "^8.2.10"
  },

yarn install then running yarn audit should yield the magic words:

0 vulnerabilities found - Packages audited: 999
✨  Done in 1.10s.
user_121373120

I managed to reduce the audit issues down to one moderate vulnerability due to the browserslist package in my post here:

https://stackoverflow.com/a/68046680/1669123

Updating postcss to version 8.x.x in resolutions results in build issues for me. I'm a web dev newcomer and guessing version 8 breaking changes for plugins is the culprit. Version 7.0.36 is the latest version 7 postcss that builds and runs for me. The changelog states that this version has the ReDoS fix backported from version 8. I can't seem to solve the browserslist package issue without it causing 'module not found' errors at runtime. I'm guessing we'll have to wait on the CRA team to update react-scripts for a more thorough solution.

user_16691230

Alternatively, you can solve it using yarn audit instead of npm.

yarn audit --groups postcss

This command will only ignore postcss package from the security check.

user_106407290
Related