diff --git a/.circleci/workflows.yml b/.circleci/workflows.yml
index 161e6be406..4d0f51a036 100644
--- a/.circleci/workflows.yml
+++ b/.circleci/workflows.yml
@@ -2,7 +2,7 @@ version: 2.1
 
 chrome-stable-version: &chrome-stable-version "138.0.7204.183"
 chrome-beta-version: &chrome-beta-version "139.0.7258.66"
-firefox-stable-version: &firefox-stable-version "137.0"
+firefox-stable-version: &firefox-stable-version "141.0"
 
 orbs:
   browser-tools: circleci/browser-tools@2.1.1
diff --git a/cli/types/cypress.d.ts b/cli/types/cypress.d.ts
index 3837ebe320..35a5d51746 100644
--- a/cli/types/cypress.d.ts
+++ b/cli/types/cypress.d.ts
@@ -3828,7 +3828,7 @@ declare namespace Cypress {
     validate?: () => Promise<false | void> | void
   }
 
-  type SameSiteStatus = 'no_restriction' | 'strict' | 'lax'
+  type SameSiteStatus = 'no_restriction' | 'strict' | 'lax' | 'unspecified'
 
   interface SelectFileOptions extends Loggable, Timeoutable, ActionableOptions {
     /**
@@ -3879,8 +3879,8 @@ declare namespace Cypress {
      */
     expiry: number
     /**
-     * The cookie's SameSite value. If set, should be one of `lax`, `strict`, or `no_restriction`.
-     * `no_restriction` is the equivalent of `SameSite=None`. Pass `undefined` to use the browser's default.
+     * The cookie's SameSite value. If set, should be one of `lax`, `strict`, `no_restriction`, or `unspecified`.
+     * `no_restriction` is the equivalent of `SameSite=None`. Pass `undefined` to use the browser's default ('unspecified' is the default for Firefox 140 and up).
      * Note: `no_restriction` can only be used if the secure flag is set to `true`.
      * @default undefined
      */
diff --git a/guides/eslint-migration.md b/guides/eslint-migration.md
index ec041e00fe..a433da03ca 100644
--- a/guides/eslint-migration.md
+++ b/guides/eslint-migration.md
@@ -108,39 +108,50 @@ For each package in the batch:
      - In each migrated package, add `@packages/eslint-config` to `devDependencies` (use a relative file path if not published to npm).
    - **Add ESLint as a dev dependency:**
      - Since `@packages/eslint-config` has ESLint as a peer dependency, add `eslint: "^9.18.0"` to `devDependencies`.
-4. **Run lint and autofix:**
+4. **Add lint-staged configuration:**
+   - Add a `lint-staged` section to the package's `package.json`:
+     ```json
+     {
+       "lint-staged": {
+         "**/*.{js,jsx,ts,tsx}": "eslint --fix"
+       }
+     }
+     ```
+   - This ensures that when files are staged for commit, they are automatically linted and fixed using the package's local ESLint configuration.
+5. **Run lint and autofix:**
    - From the package root, run:
      ```
      npx eslint . --ext .js,.ts,.tsx,.jsx --fix
      ```
    - Manually fix any remaining lint errors.
-5. **Verify TypeScript configuration:**
+6. **Verify TypeScript configuration:**
    - Ensure the package has a valid `tsconfig.json` that works with the new ESLint config.
    - Run `npx tsc --noEmit` to check for TypeScript compilation errors.
    - Verify that the new ESLint config can properly parse TypeScript files in the package.
-6. **Run tests for the package** to ensure nothing broke.
-7. **Commit changes** with a clear message, e.g.:
+7. **Run tests for the package** to ensure nothing broke.
+8. **Commit changes** with a clear message, e.g.:
    ```
    chore(npm/grep): migrate to @packages/eslint-config and remove legacy eslint-plugin-dev
    ```
 
-### 3. **Open a PR for Each Batch**
+### 4. **Open a PR for Each Batch**
 - Keep each migration PR focused (one batch per PR).
 - List all affected packages in the PR description.
 - Include a checklist for each package:
   - [ ] Removed old ESLint config
   - [ ] Added new config
+  - [ ] Added lint-staged configuration
   - [ ] Ran lint and fixed errors
   - [ ] Ran tests
 
-### 4. **Document Issues or Gaps**
+### 5. **Document Issues or Gaps**
 - If you hit any missing rules or plugin gaps, note them for follow-up.
 - If a package needs a custom override, add it in a local `eslint.config.ts` (prefer to upstream to the shared config if possible).
 
-### 5. **Deprecate and Remove Old Plugin**
+### 6. **Deprecate and Remove Old Plugin**
 - Once all packages are migrated, remove `@cypress/eslint-plugin-dev` from the repo and CI.
 
-### 6. **Simplify Lint-Staged Configuration**
+### 7. **Simplify Lint-Staged Configuration**
 After all packages are migrated, simplify the lint-staged configuration in root `package.json`:
 
 ```json
@@ -152,7 +163,7 @@ After all packages are migrated, simplify the lint-staged configuration in root
 }
 ```
 
-### 7. **Update Lerna/Monorepo Config**
+### 8. **Update Lerna/Monorepo Config**
 - Ensure all packages reference the new config in their `package.json`/`eslint.config.ts`.
 - Update documentation and developer onboarding guides.
 
@@ -317,6 +328,7 @@ For each package, ensure you've completed:
 - [ ] Removed `.eslintrc*` files
 - [ ] Created `eslint.config.ts` with proper configuration
 - [ ] Added required dependencies (`eslint`, `@packages/eslint-config`, `jiti`)
+- [ ] Added lint-staged configuration to `package.json`
 - [ ] Created/updated `tsconfig.json` that extends base config
 - [ ] Updated ESLint scripts (removed `--ext` flag)
 - [ ] Ran `yarn lint` successfully
diff --git a/npm/grep/package.json b/npm/grep/package.json
index 8836a95f98..cc075e7a40 100644
--- a/npm/grep/package.json
+++ b/npm/grep/package.json
@@ -40,6 +40,9 @@
     "cypress",
     "grep"
   ],
+  "lint-staged": {
+    "**/*.{js,jsx,ts,tsx,json}": "eslint --fix"
+  },
   "resolutions": {
     "jiti": "^2.4.2"
   },
diff --git a/package.json b/package.json
index dbd4539609..d32f87a7d5 100644
--- a/package.json
+++ b/package.json
@@ -265,27 +265,7 @@
     ]
   },
   "lint-staged": {
-    "npm/grep/**/*.{js,jsx,ts,tsx}": "yarn lint:fix",
-    "*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "cli/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "packages/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "scripts/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "system-tests/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "tooling/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/angular/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/cypress-schematic/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/eslint-plugin-dev/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/mount-utils/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/puppeteer/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/react/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/svelte/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/vite-dev-server/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/vite-plugin-cypress-esm/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/vue/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/webpack-batteries-included-preprocessor/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/webpack-dev-server/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/webpack-preprocessor/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
-    "npm/xpath/**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
+    "**/*.{js,jsx,ts,tsx,json,eslintrc,vue}": "eslint --fix",
     "*workflows.yml": "node scripts/format-workflow-file.js"
   },
   "resolutions": {
diff --git a/packages/driver/cypress/e2e/commands/cookies.cy.js b/packages/driver/cypress/e2e/commands/cookies.cy.js
index 15cbc01643..ca87b1c9d9 100644
--- a/packages/driver/cypress/e2e/commands/cookies.cy.js
+++ b/packages/driver/cypress/e2e/commands/cookies.cy.js
@@ -1374,10 +1374,17 @@ describe('src/cy/commands/cookies', () => {
 
       cy.setCookie('five', 'bar')
 
-      // @see https://bugzilla.mozilla.org/show_bug.cgi?id=1624668
-      // TODO(webkit): pw webkit has the same issue as firefox (no "unspecified" state), need a patched binary
-      if (Cypress.isBrowser('firefox') || Cypress.isBrowser('webkit')) {
-        cy.getCookie('five').should('include', { sameSite: 'no_restriction' })
+      // @see https://bugzilla.mozilla.org/show_bug.cgi?id=1550032
+      // Firefox bidi returns "unspecified" for sameSite;
+      // webkit & firefox < 135 return "no_restriction" for sameSite;
+      // other browsers do not return sameSite at all
+      const sameSite = (
+        Cypress.isBrowser('webkit')
+      ) ? 'no_restriction' :
+        Cypress.isBrowser('firefox') ? 'unspecified' : null
+
+      if (sameSite) {
+        cy.getCookie('five').should('include', { sameSite })
       } else {
         cy.getCookie('five').should('not.have.property', 'sameSite')
       }
@@ -1515,7 +1522,7 @@ describe('src/cy/commands/cookies', () => {
           assertLogLength(this.logs, 1)
           expect(lastLog.get('error').message).to.eq(stripIndent`
             If a \`sameSite\` value is supplied to \`cy.setCookie()\`, it must be a string from the following list:
-              > no_restriction, lax, strict
+              > no_restriction, lax, strict, unspecified
             You passed:
               > bad`)
 
diff --git a/packages/driver/cypress/e2e/e2e/e2e_cookies.cy.js b/packages/driver/cypress/e2e/e2e/e2e_cookies.cy.js
index cd7512b0de..c78f5675c0 100644
--- a/packages/driver/cypress/e2e/e2e/e2e_cookies.cy.js
+++ b/packages/driver/cypress/e2e/e2e/e2e_cookies.cy.js
@@ -8,7 +8,7 @@ const cleanse = (cookies) => {
   })
 }
 
-const firefoxDefaultSameSite = Cypress.isBrowser({ family: 'firefox' }) ? { sameSite: 'no_restriction' } : {}
+const firefoxDefaultSameSite = Cypress.isBrowser({ family: 'firefox' }) ? { sameSite: 'unspecified' } : {}
 
 describe('e2e cookies spec', () => {
   it('simple cookie', () => {
diff --git a/packages/driver/cypress/e2e/e2e/origin/cookie_login.cy.ts b/packages/driver/cypress/e2e/e2e/origin/cookie_login.cy.ts
index a747a1ec4b..23742ec6e7 100644
--- a/packages/driver/cypress/e2e/e2e/origin/cookie_login.cy.ts
+++ b/packages/driver/cypress/e2e/e2e/origin/cookie_login.cy.ts
@@ -192,8 +192,7 @@ describe('cy.origin - cookie login', { browser: '!webkit' }, () => {
       verifyIdpNotLoggedIn({ expectNullCookie: false })
     })
 
-    // FIXME: Currently in Firefox, the default cookie setting in the extension is no_restriction, which can be set with Secure=false.
-    it('SameSite=None -> not logged in', { browser: '!firefox' }, () => {
+    it('SameSite=None -> not logged in', () => {
       cy.origin('http://www.foobar.com:3500', { args: { username } }, ({ username }) => {
         cy.get('[data-cy="username"]').type(username)
         cy.get('[data-cy="cookieProps"]').type('SameSite=None')
diff --git a/packages/driver/src/cy/commands/cookies.ts b/packages/driver/src/cy/commands/cookies.ts
index 741c230d32..da9e92e708 100644
--- a/packages/driver/src/cy/commands/cookies.ts
+++ b/packages/driver/src/cy/commands/cookies.ts
@@ -21,7 +21,7 @@ function pickCookieProps (cookie) {
 // different defaults, and Firefox lacks support for `unspecified`, so
 // `undefined` is used in lieu of `unspecified`
 // @see https://bugzilla.mozilla.org/show_bug.cgi?id=1624668
-const VALID_SAMESITE_VALUES = ['no_restriction', 'lax', 'strict']
+const VALID_SAMESITE_VALUES = ['no_restriction', 'lax', 'strict', 'unspecified']
 
 function normalizeSameSite (sameSite?: string) {
   if (_.isUndefined(sameSite)) {
diff --git a/packages/eslint-config/package.json b/packages/eslint-config/package.json
index fa8d539c21..60b5a6507c 100644
--- a/packages/eslint-config/package.json
+++ b/packages/eslint-config/package.json
@@ -27,5 +27,8 @@
   },
   "peerDependencies": {
     "eslint": "^9.31.0"
+  },
+  "lint-staged": {
+    "**/*.{js,jsx,ts,tsx,json}": "eslint --fix"
   }
 }
diff --git a/packages/server/lib/browsers/firefox.ts b/packages/server/lib/browsers/firefox.ts
index f6f1793bf2..14efa53759 100644
--- a/packages/server/lib/browsers/firefox.ts
+++ b/packages/server/lib/browsers/firefox.ts
@@ -556,6 +556,8 @@ export async function open (browser: Browser, url: string, options: BrowserLaunc
 
   debug('launch in firefox', { url, args: launchOptions.args })
 
+  const launchEnvs = process.env
+
   const geckoDriverOptions: GeckodriverParameters = {
     host: '127.0.0.1',
     // geckodriver port is assigned under the hood by @wdio/utils
@@ -572,7 +574,7 @@ export async function open (browser: Browser, url: string, options: BrowserLaunc
       stdio: ['ignore', 'pipe', 'pipe'],
       env: {
         ...BROWSER_ENVS,
-        ...process.env,
+        ...launchEnvs,
       },
     },
     jsdebugger: Debug.enabled(GECKODRIVER_DEBUG_NAMESPACE_VERBOSE) || false,
diff --git a/packages/server/test/unit/browsers/firefox_spec.ts b/packages/server/test/unit/browsers/firefox_spec.ts
index c082450eff..49f8ca5faa 100644
--- a/packages/server/test/unit/browsers/firefox_spec.ts
+++ b/packages/server/test/unit/browsers/firefox_spec.ts
@@ -65,7 +65,7 @@ describe('lib/browsers/firefox', () => {
   context('#open', () => {
     beforeEach(function () {
       // majorVersion >= 135 indicates BiDi support for Firefox
-      this.browser = { name: 'firefox', channel: 'stable', majorVersion: 135, path: '/path/to/binary' }
+      this.browser = { name: 'firefox', family: 'firefox', channel: 'stable', majorVersion: 135, path: '/path/to/binary' }
       this.automation = {
         use: sinon.stub().returns({}),
       }
diff --git a/scripts/gulp/monorepoPaths.ts b/scripts/gulp/monorepoPaths.ts
index 225d399431..bf2358f1c8 100644
--- a/scripts/gulp/monorepoPaths.ts
+++ b/scripts/gulp/monorepoPaths.ts
@@ -11,6 +11,7 @@ export const monorepoPaths = {
   pkgDriver: path.join(__dirname, '../../packages/driver'),
   pkgElectron: path.join(__dirname, '../../packages/electron'),
   pkgErrors: path.join(__dirname, '../../packages/errors'),
+  pkgEslintConfig: path.join(__dirname, '../../packages/eslint-config'),
   pkgExample: path.join(__dirname, '../../packages/example'),
   pkgExtension: path.join(__dirname, '../../packages/extension'),
   pkgFrontendShared: path.join(__dirname, '../../packages/frontend-shared'),
diff --git a/system-tests/lib/system-tests.ts b/system-tests/lib/system-tests.ts
index d74ca82fb7..82dd6c4af3 100644
--- a/system-tests/lib/system-tests.ts
+++ b/system-tests/lib/system-tests.ts
@@ -613,7 +613,12 @@ const systemTests = {
       const s = this.servers
 
       if (s) {
-        await Bluebird.map(s, stopServer)
+        try {
+          await Bluebird.map(s, stopServer)
+        } catch (err) {
+          console.error('Error stopping server', err)
+          throw err
+        }
       }
     })
   },
diff --git a/system-tests/projects/e2e/cypress/e2e/cookies_spec_baseurl.cy.js b/system-tests/projects/e2e/cypress/e2e/cookies_spec_baseurl.cy.js
index 86f254e2ef..c0813d74cf 100644
--- a/system-tests/projects/e2e/cypress/e2e/cookies_spec_baseurl.cy.js
+++ b/system-tests/projects/e2e/cypress/e2e/cookies_spec_baseurl.cy.js
@@ -11,9 +11,9 @@ const otherHttpsUrl = Cypress.env('otherHttpsUrl')
 let defaultSameSite = undefined
 
 if (Cypress.isBrowser('firefox')) {
-  // firefox will default to "no_restriction"
+  // firefox will default to "unspecified"
   // @see https://bugzilla.mozilla.org/show_bug.cgi?id=1624668
-  defaultSameSite = 'no_restriction'
+  defaultSameSite = 'unspecified'
 }
 
 describe('cookies', () => {
diff --git a/system-tests/projects/e2e/cypress/e2e/multi_cookies.cy.js b/system-tests/projects/e2e/cypress/e2e/multi_cookies.cy.js
index 0a6f6efd0a..8baebeeae1 100644
--- a/system-tests/projects/e2e/cypress/e2e/multi_cookies.cy.js
+++ b/system-tests/projects/e2e/cypress/e2e/multi_cookies.cy.js
@@ -64,7 +64,13 @@ describe('set:cookies', () => {
         'domain': '127.0.0.3',
         'secure': false,
         'httpOnly': false,
-        ...(Cypress.isBrowser({ family: 'firefox' }) ? { sameSite: 'no_restriction' } : {}),
+        ...(
+          Cypress.isBrowser('webkit')
+            ? { sameSite: 'no_restriction' }
+            : Cypress.isBrowser({ family: 'firefox' }) ?
+              { sameSite: 'unspecified' } :
+              {}
+        ),
       },
 
       {
diff --git a/system-tests/projects/e2e/cypress/e2e/request.cy.js b/system-tests/projects/e2e/cypress/e2e/request.cy.js
index f6f8229555..3963e186fb 100644
--- a/system-tests/projects/e2e/cypress/e2e/request.cy.js
+++ b/system-tests/projects/e2e/cypress/e2e/request.cy.js
@@ -32,7 +32,7 @@ describe('redirects + requests', () => {
       }
 
       if (Cypress.isBrowser('firefox')) {
-        expectedCookie.sameSite = 'no_restriction'
+        expectedCookie.sameSite = 'unspecified'
       }
 
       expect(cookies[1]).to.deep.eq(expectedCookie)