Error: error:0308010C:digital envelope routines::unsupported (code: 'ERR_OSSL_EVP_UNSUPPORTED') when running npm start / build with webpack 4, Create React App 4 or old Vue CLI / Angular on Node 17+

Cause: Node.js 17 and later use OpenSSL 3, which disables old hash algorithms such as MD4 by default. webpack 4 (used by Create React App 4, Vue CLI 4, older Angular, Storybook 6 and others) hashes modules with MD4, so the build crashes with ERR_OSSL_EVP_UNSUPPORTED as soon as you run it on Node 18, 20, 22 or newer. How to check: run node -v (17 or higher) and npm ls webpack. If webpack is 4.x, or an old 5.x, this is the cause. Fix (best first): 1. Upgrade the build tool so it no longer needs MD4: move to webpack 5 (current releases include their own MD4 implementation and support output.hashFunction: 'xxhash64'), react-scripts 5, Vue CLI 5 or Vite, or a current Angular CLI. This is the lasting fix. 2. If you can't upgrade yet, allow the legacy algorithms for the build only: set NODE_OPTIONS=--openssl-legacy-provider in the build script (cross-platform with cross-env, for example "start": "cross-env NODE_OPTIONS=--openssl-legacy-provider react-scripts start"). Scope it to the build so the rest of your Node processes keep the default OpenSSL settings. 3. Don't pin the project to Node 16: it has been end of life since 2023 and no longer gets security fixes. After: run a clean build (delete node_modules/.cache), and if you used the flag, add a task to remove it once the toolchain is upgraded. Note that on Node 16 or older, passing --openssl-legacy-provider is itself an error ('bad option'), so set it only where Node 17+ is used. Sources: https://nodejs.org/api/cli.html#--openssl-legacy-provider https://sentry.io/answers/error-error-0308010c-digital-envelope-routines-unsupported-next-js https://webpack.js.org/configuration/output/#outputhashfunction