[BUG] Blocked `postinstall` execution for remote installation - `allowScripts` not recognized (npm@12.0.0)

[MikeMcC399]

• follows on from [BUG] ENOMATCH "no trusted identity for policy key" for install-scripts after remote install #9723 for npm 11.18.0

Is there an existing issue for this?

• I have searched the existing issues

This issue exists in the latest npm version

• I am using the latest npm

This is not just a request to bump a dependency for a CVE

• This is not solely a request to bump a dependency for a CVE

Current Behavior

npm 12.0.0 blocks postinstall execution after installing from remote URL
ENOMATCH warning
does not recognize existing allowScripts

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found 0 vulnerabilities
npm warn install-scripts 1 package had install scripts blocked because they are not covered by allowScripts:
npm warn install-scripts   cypress@15.18.1 (postinstall: node dist/index.js --exec install)
npm warn install-scripts
npm warn install-scripts Run `npm install-scripts ls` to review, or `npm install-scripts approve <pkg>` to allow.
cy-npm-install-test@ /home/mike/github/TESTING/cy-npm-install-test
└── cypress@15.18.1

npm warn install-scripts skipping cypress: no trusted identity for policy key
npm error code ENOMATCH
npm error No installed packages match: cypress
npm error A complete log of this run can be found in: /home/mike/.npm/_logs/2026-07-09T04_40_55_501Z-debug-0.log

In the case of Cypress, the workaround is to run npx cypress install to manually run the postinstall script.

Expected Behavior

npm should allow installation from a remote CDN and accept the allowScripts setting. If additional configs are necessary for this to work, then they should be documented.

Steps To Reproduce

Execute the following:

cat > package.json <<EOT
{
  "allowScripts": {
    "cypress": true
  }
}
EOT
npm set allow-remote=all --location=project
rm -rf ~/.cache/Cypress
npm install https://cdn.cypress.io/beta/npm/15.18.1/linux-x64/develop-8addb93e04dd372ab736d76c60735711d570312e/cypress.tgz
npm ls cypress
npm install-scripts approve cypress

See also https://docs.cypress.io/app/references/advanced-installation#Install-pre-release-version

Environment

• npm: 12.0.0
• Node.js: 26.5.0
• OS Name: Ubuntu 26.04 LTS
• System Model Name: HP x64 desktop
• npm config:

; "project" config from /home/mike/github/TESTING/cy-npm-install-test/.npmrc

allow-remote = "all"

; node bin location = /home/mike/n/bin/node
; node version = v26.5.0
; npm local prefix = /home/mike/github/TESTING/cy-npm-install-test
; npm version = 12.0.0
; cwd = /home/mike/github/TESTING/cy-npm-install-test
; HOME = /home/mike
; Run `npm config ls -l` to show all defaults.