Firefox >=138.x "Sandbox: CanCreateUserNamespace() clone() failure: EPERM" #1343
Description
Current behavior
When Cypress is run against Firefox >=138.x using a Cypress Docker image, then an error similar to the following error is shown in the logs:
[322] Sandbox: CanCreateUserNamespace() clone() failure: EPERM
The test does however continue and is successful.
The issue has been observed in CircleCI and GitHub Actions.
Desired behavior
There should be no error message similar to the following in the logs when running Cypress in a Docker container against Firefox:
[322] Sandbox: CanCreateUserNamespace() clone() failure: EPERM
Test code to reproduce
View CircleCI logs https://app.circleci.com/pipelines/github/cypress-io/cypress-docker-images?branch=master, for example
https://app.circleci.com/pipelines/github/cypress-io/cypress-docker-images/2540
and https://app.circleci.com/pipelines/github/cypress-io/cypress-docker-images/2540/workflows/e49c3bd9-1775-43a2-a588-d1a87b59fd84/jobs/78549?invite=true#step-104-3319_62
Also in GitHub Actions
https://github.com/cypress-io/github-action/actions/workflows/example-docker.yml
To reproduce locally:
git clone https://github.com/cypress-io/cypress-docker-images
cd cypress-docker-images
cd examples/basic-mini
docker run -it --rm -v .:/app -w /app --entrypoint cypress cypress/included run -b firefoxCypress Version
First reported on Cypress: 14.3.3
Continues to be reproducible on Cypress: 15.2.0
Docker image
cypress/browsers:22.15.0 or
custom image with Firefox 138.0
Firefox version
=
138.0
Node version
v22.15.0 LTS & 22.15.1 LTS
Operating System
Ubuntu 24.04.3 LTS
Debian 13.0
Debug Logs
Run npx cypress run --browser firefox
[STARTED] Task without title.
[SUCCESS] Task without title.
DevTools listening on ws://127.0.0.1:34721/devtools/browser/21cda210-4026-47c5-9c9e-d5044d42719e
====================================================================================================
(Run Starting)
┌────────────────────────────────────────────────────────────────────────────────────────────
│ Cypress: 14.3.3 │
│ Browser: Firefox 138 (headless) │
│ Node Version: v22.15.0 (/usr/local/bin/node) │
│ Specs: 1 found (spec.cy.js) │
│ Searched: cypress/e2e/**/*.cy.{js,jsx,ts,tsx} │
└────────────────────────────────────────────────────────────────────────────────────────────
─────────────────────────────────────────────────────────────────────────────────────────────
Running: spec.cy.js (1 of 1)
cypress:server:browsers:firefox firefox open { browser: { name: 'firefox', family: 'firefox', channel: 'stable', displayName: 'Firefox', version: '138.0.1', path: 'firefox', majorVersion: '138', isHeadless: true, isHeaded: false }, url: 'http://localhost:42339/__/#/specs/runner?file=cypress/e2e/spec.cy.js', browsers: [ { name: 'chrome', family: 'chromium', channel: 'stable', displayName: 'Chrome', version: '136.0.7103.92', path: 'google-chrome', majorVersion: '136' }, { name: 'firefox', family: 'firefox', channel: 'stable', displayName: 'Firefox', version: '138.0.1', path: 'firefox', majorVersion: '138' }, { name: 'edge', family: 'chromium', channel: 'stable', displayName: 'Edge', version: '136.0.3240.50', path:
cypress:server:browsers:firefox available ports: { marionettePort: 35471, webDriverBiDiPort: 36225 } +3ms
cypress:server:browsers:firefox firefox directories { path: '/github/home/.config/Cypress/cy/production/browsers/firefox-stable/run-609', cacheDir: '/github/home/.config/Cypress/cy/production/browsers/firefox-stable/run-609/CypressCache', extensionDest: '/github/home/.config/Cypress/cy/production/browsers/firefox-stable/run-609/CypressExtension' } +39ms
cypress:server:browsers:firefox launching geckodriver with browser envs { MOZ_REMOTE_SETTINGS_DEVTOOLS: '1', MOZ_HEADLESS_WIDTH: '1280', MOZ_HEADLESS_HEIGHT: '720' } +1ms
cypress:server:browsers:firefox launch in firefox {
url: 'http://localhost:42339/__/#/specs/runner?file=cypress/e2e/spec.cy.js',
args: [
'-new-instance',
'-start-debugger-server',
'-no-remote',
'-headless'
]
} +0ms
[903] Sandbox: CanCreateUserNamespace() clone() failure: EPERM
cypress:server:browsers:firefox firefox running on pid: 912 +2s
cypress:server:browsers:firefox webdriver running on pid: 906 +0ms
cypress:server:browsers:firefox installing extension at path: /github/home/.config/Cypress/cy/production/browsers/firefox-stable/run-609/CypressExtension +0ms
cypress:server:browsers:firefox extension with id automation-extension@cypress.io installed! +80ms
cypress:server:browsers:firefox setting up firefox utils +0ms
test local demo page
cypress:server:browsers:firefox Closing extra targets is not currently supported in Firefox +2s
✓ heading (87ms)
1 passing (111ms)
(Results)
┌────────────────────────────────────────────────────────────────────────────────────────────
│ Tests: 1 │
│ Passing: 1 │
│ Failing: 0 │
│ Pending: 0 │
│ Skipped: 0 │
│ Screenshots: 0 │
│ Video: false │
│ Duration: 0 seconds │
│ Spec Ran: spec.cy.js │
└────────────────────────────────────────────────────────────────────────────────────────────
====================================================================================================
(Run Finished)
Spec Tests Passing Failing Pending Skipped
┌────────────────────────────────────────────────────────────────────────────────────────────
│ ✔ spec.cy.js 107ms 1 1 - - - │
└────────────────────────────────────────────────────────────────────────────────────────────
✔ All specs passed! 107ms 1 1 - - -
cypress:server:browsers:firefox clearing instance state +183ms
cypress:server:browsers:firefox unbinding bidi client events +0ms
cypress:server:browsers:firefox closing firefox +0ms
cypress:server:browsers:firefox closing geckodriver and webdriver +0ms
cypress:server:browsers:firefox clearing instance state +1ms