diff --git a/.changeset/selfish-donkeys-cheer.md b/.changeset/selfish-donkeys-cheer.md
new file mode 100644
index 00000000000..7cf6946520c
--- /dev/null
+++ b/.changeset/selfish-donkeys-cheer.md
@@ -0,0 +1,5 @@
+---
+'firebase': patch
+---
+
+Fix glob pattern to work with Node 20 and its NPM version.
diff --git a/.changeset/thirty-otters-hug.md b/.changeset/thirty-otters-hug.md
new file mode 100644
index 00000000000..6dd0c7e0059
--- /dev/null
+++ b/.changeset/thirty-otters-hug.md
@@ -0,0 +1,5 @@
+---
+'@firebase/auth': patch
+---
+
+Fix possible XSS vulnerability through **FIREBASE_DEFAULTS** settings.
diff --git a/.changeset/violet-ways-judge.md b/.changeset/violet-ways-judge.md
new file mode 100644
index 00000000000..a845151cc84
--- /dev/null
+++ b/.changeset/violet-ways-judge.md
@@ -0,0 +1,2 @@
+---
+---
diff --git a/.github/workflows/canary-deploy.yml b/.github/workflows/canary-deploy.yml
index 02871078f44..73ce0044c1a 100644
--- a/.github/workflows/canary-deploy.yml
+++ b/.github/workflows/canary-deploy.yml
@@ -31,10 +31,10 @@ jobs:
       with:
         # Canary release script requires git history and tags.
         fetch-depth: 0
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Yarn install
       run: yarn
     - name: Deploy canary
diff --git a/.github/workflows/check-changeset.yml b/.github/workflows/check-changeset.yml
index a851bb4793f..ca76fe7a76b 100644
--- a/.github/workflows/check-changeset.yml
+++ b/.github/workflows/check-changeset.yml
@@ -34,10 +34,10 @@ jobs:
       with:
         # This makes Actions fetch all Git history so check_changeset script can diff properly.
         fetch-depth: 0
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Yarn install
       run: yarn
     - name: Run changeset script
diff --git a/.github/workflows/check-docs.yml b/.github/workflows/check-docs.yml
index 9c44c22214a..aefab2506e3 100644
--- a/.github/workflows/check-docs.yml
+++ b/.github/workflows/check-docs.yml
@@ -27,10 +27,10 @@ jobs:
       with:
         # get all history for the diff
         fetch-depth: 0
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Yarn install
       run: yarn
     - name: Run doc generation (devsite docs)
diff --git a/.github/workflows/check-pkg-paths.yml b/.github/workflows/check-pkg-paths.yml
index 2182a3502c6..8ca54225e10 100644
--- a/.github/workflows/check-pkg-paths.yml
+++ b/.github/workflows/check-pkg-paths.yml
@@ -27,10 +27,10 @@ jobs:
       with:
         # This makes Actions fetch all Git history so run-changed script can diff properly.
         fetch-depth: 0
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Yarn install
       run: yarn
     - name: Yarn build
diff --git a/.github/workflows/deploy-config.yml b/.github/workflows/deploy-config.yml
index ebb607c5417..cc8e5925302 100644
--- a/.github/workflows/deploy-config.yml
+++ b/.github/workflows/deploy-config.yml
@@ -34,10 +34,10 @@ jobs:
       with:
         # This makes Actions fetch all Git history so run-changed script can diff properly.
         fetch-depth: 0
-    - name: Set up node (18)
+    - name: Set up node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 18.x
+        node-version: 20.x
     - name: Yarn install
       run: yarn
     - name: Deploy project config if needed
diff --git a/.github/workflows/e2e-test.yml b/.github/workflows/e2e-test.yml
index d844e4e34ea..80a555f7840 100644
--- a/.github/workflows/e2e-test.yml
+++ b/.github/workflows/e2e-test.yml
@@ -36,10 +36,10 @@ jobs:
     steps:
       - name: Checkout Repo
         uses: actions/checkout@master
-      - name: Set up Node (18)
+      - name: Set up Node (20)
         uses: actions/setup-node@master
         with:
-          node-version: 18.x
+          node-version: 20.x
       - name: install Chrome stable
         run: |
           sudo apt-get update
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
index 1e77356832d..7434a9cab4c 100644
--- a/.github/workflows/format.yml
+++ b/.github/workflows/format.yml
@@ -31,10 +31,10 @@ jobs:
       with:
         # get all history for the diff
         fetch-depth: 0
-    - name: Set up node (16)
+    - name: Set up node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Yarn install
       run: yarn
     - name: Run formatting script
diff --git a/.github/workflows/health-metrics-pull-request.yml b/.github/workflows/health-metrics-pull-request.yml
index 6bbfc8b93c2..45f1aa1ab44 100644
--- a/.github/workflows/health-metrics-pull-request.yml
+++ b/.github/workflows/health-metrics-pull-request.yml
@@ -41,7 +41,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - uses: 'google-github-actions/auth@v0'
         with:
           credentials_json: '${{ secrets.GCP_SA_KEY }}'
@@ -58,7 +58,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - uses: 'google-github-actions/auth@v0'
         with:
           credentials_json: '${{ secrets.GCP_SA_KEY }}'
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 50664c261cb..80851d9834a 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -23,10 +23,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
-    - name: Set up node (16)
+    - name: Set up node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: yarn install
       run: yarn
     - name: yarn lint
diff --git a/.github/workflows/prerelease-manual-deploy.yml b/.github/workflows/prerelease-manual-deploy.yml
index a1b0af0e258..54f75383f95 100644
--- a/.github/workflows/prerelease-manual-deploy.yml
+++ b/.github/workflows/prerelease-manual-deploy.yml
@@ -34,10 +34,10 @@ jobs:
           with:
             # Canary release script requires git history and tags.
             fetch-depth: 0
-        - name: Set up node (16)
+        - name: Set up node (20)
           uses: actions/setup-node@v3
           with:
-            node-version: 16.x
+            node-version: 20.x
         - name: Yarn install
           run: yarn
         - name: Deploy prerelease
diff --git a/.github/workflows/release-log.yml b/.github/workflows/release-log.yml
index 235a0d142ce..780e3e97b52 100644
--- a/.github/workflows/release-log.yml
+++ b/.github/workflows/release-log.yml
@@ -28,10 +28,10 @@ jobs:
       - name: Checkout Repo
         uses: actions/checkout@master
 
-      - name: Setup Node.js 16.x
+      - name: Setup Node.js 20.x
         uses: actions/setup-node@master
         with:
-          node-version: 16.x
+          node-version: 20.x
 
       - name: Get PR number and send to tracker.
         run: node scripts/ci/log-changesets.js
diff --git a/.github/workflows/release-pr.yml b/.github/workflows/release-pr.yml
index 02dc8e3cef5..04ebbd8b926 100644
--- a/.github/workflows/release-pr.yml
+++ b/.github/workflows/release-pr.yml
@@ -32,10 +32,10 @@ jobs:
           # This makes Actions fetch all Git history so that Changesets can generate changelogs with the correct commits
           fetch-depth: 0
 
-      - name: Setup Node.js 16.x
+      - name: Setup Node.js 20.x
         uses: actions/setup-node@master
         with:
-          node-version: 16.x
+          node-version: 20.x
 
       - name: Install Dependencies
         run: yarn
diff --git a/.github/workflows/release-prod.yml b/.github/workflows/release-prod.yml
index 684f405a9ac..09d1797ec4c 100644
--- a/.github/workflows/release-prod.yml
+++ b/.github/workflows/release-prod.yml
@@ -32,10 +32,10 @@ jobs:
       contents: write
 
     steps:
-    - name: Set up node (16)
+    - name: Set up node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Checkout release branch (with history)
       uses: actions/checkout@master
       with:
diff --git a/.github/workflows/release-staging.yml b/.github/workflows/release-staging.yml
index 5b0e2a7cb5f..6a687ed5ee2 100644
--- a/.github/workflows/release-staging.yml
+++ b/.github/workflows/release-staging.yml
@@ -46,10 +46,10 @@ jobs:
     # Block this workflow if run on a non-release branch.
     if: github.event.inputs.release-branch == 'release' || endsWith(github.event.inputs.release-branch, '-releasebranch')
     steps:
-    - name: Set up node (16)
+    - name: Set up node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Merge master into release
       uses: actions/github-script@v6
       with:
diff --git a/.github/workflows/release-tweet.yml b/.github/workflows/release-tweet.yml
index af6379ceb18..edd2634637b 100644
--- a/.github/workflows/release-tweet.yml
+++ b/.github/workflows/release-tweet.yml
@@ -34,10 +34,10 @@ jobs:
     steps:
       - name: Checkout Repo
         uses: actions/checkout@master
-      - name: Setup Node.js 16.x
+      - name: Setup Node.js 20.x
         uses: actions/setup-node@master
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: Poll release notes page on devsite
         run: node scripts/ci/poll_release_notes.js
         env:
diff --git a/.github/workflows/test-all.yml b/.github/workflows/test-all.yml
index e72dca55c8b..fce2b722814 100644
--- a/.github/workflows/test-all.yml
+++ b/.github/workflows/test-all.yml
@@ -42,10 +42,10 @@ jobs:
       run: |
         npx @puppeteer/browsers install chrome@stable
     - uses: actions/checkout@v3
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Test setup and yarn install
       run: |
         cp config/ci.config.json config/project.json
@@ -81,10 +81,10 @@ jobs:
         name: build.tar.gz
     - name: Unzip build artifact
       run: tar xf build.tar.gz
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Test setup and yarn install
       run: |
         cp config/ci.config.json config/project.json
@@ -132,10 +132,10 @@ jobs:
         name: build.tar.gz
     - name: Unzip build artifact
       run: tar xf build.tar.gz
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Test setup and yarn install
       run: |
         cp config/ci.config.json config/project.json
@@ -175,10 +175,10 @@ jobs:
         name: build.tar.gz
     - name: Unzip build artifact
       run: tar xf build.tar.gz
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Test setup and yarn install
       run: |
         cp config/ci.config.json config/project.json
@@ -219,10 +219,10 @@ jobs:
         name: build.tar.gz
     - name: Unzip build artifact
       run: tar xf build.tar.gz
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - run: cp config/ci.config.json config/project.json
     - run: yarn
     - run: yarn build:${{ matrix.persistence }}
diff --git a/.github/workflows/test-changed-auth.yml b/.github/workflows/test-changed-auth.yml
index eafb3a2d556..d2f11f2bf2f 100644
--- a/.github/workflows/test-changed-auth.yml
+++ b/.github/workflows/test-changed-auth.yml
@@ -56,10 +56,10 @@ jobs:
         with:
           # This makes Actions fetch all Git history so run-changed script can diff properly.
           fetch-depth: 0
-      - name: Set up Node (16)
+      - name: Set up Node (20)
         uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: Test setup and yarn install
         run: |
           cp config/ci.config.json config/project.json
@@ -88,10 +88,10 @@ jobs:
         with:
           # This makes Actions fetch all Git history so run-changed script can diff properly.
           fetch-depth: 0
-      - name: Set up Node (16)
+      - name: Set up Node (20)
         uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: Test setup and yarn install
         run: |
           cp config/ci.config.json config/project.json
diff --git a/.github/workflows/test-changed-fcm-integration.yml b/.github/workflows/test-changed-fcm-integration.yml
index bac3a772428..affb4639b1b 100644
--- a/.github/workflows/test-changed-fcm-integration.yml
+++ b/.github/workflows/test-changed-fcm-integration.yml
@@ -38,10 +38,10 @@ jobs:
       with:
         # This makes Actions fetch all Git history so run-changed script can diff properly.
         fetch-depth: 0
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Test setup and yarn install
       run: |
         cp config/ci.config.json config/project.json
diff --git a/.github/workflows/test-changed-firestore-integration.yml b/.github/workflows/test-changed-firestore-integration.yml
index 106aef667e7..3cc14c99c55 100644
--- a/.github/workflows/test-changed-firestore-integration.yml
+++ b/.github/workflows/test-changed-firestore-integration.yml
@@ -63,10 +63,10 @@ jobs:
         rm -f "$output_file"
       continue-on-error: true
 
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: install Chrome stable
       run: |
         sudo apt-get update
diff --git a/.github/workflows/test-changed-firestore.yml b/.github/workflows/test-changed-firestore.yml
index c34e4e79dce..9f241898e0e 100644
--- a/.github/workflows/test-changed-firestore.yml
+++ b/.github/workflows/test-changed-firestore.yml
@@ -37,10 +37,10 @@ jobs:
         with:
           # This makes Actions fetch all Git history so run-changed script can diff properly.
           fetch-depth: 0
-      - name: Set up Node (16)
+      - name: Set up Node (20)
         uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: install Chrome stable
         run: |
           sudo apt-get update
@@ -84,10 +84,10 @@ jobs:
     needs: build
     if: ${{ needs.build.outputs.changed == 'true'}}
     steps:
-      - name: Set up Node (16)
+      - name: Set up Node (20)
         uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: install Chrome stable
         run: |
           sudo apt-get update
@@ -112,10 +112,10 @@ jobs:
     needs: build
     if: ${{ needs.build.outputs.changed == 'true'}}
     steps:
-      - name: Set up Node (16)
+      - name: Set up Node (20)
         uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: install Chrome stable
         run: |
           sudo apt-get update
@@ -142,10 +142,10 @@ jobs:
     needs: build
     if: ${{ github.event_name != 'pull_request' }}
     steps:
-      - name: Set up Node (16)
+      - name: Set up Node (20)
         uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: install Chrome stable
         run: |
           sudo apt-get update
@@ -180,10 +180,10 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get install firefox
-      - name: Set up Node (16)
+      - name: Set up Node (20)
         uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: Download build archive
         uses: actions/download-artifact@v3
         with:
@@ -219,10 +219,10 @@ jobs:
           name: build.tar.gz
       - name: Unzip build artifact
         run: tar xf build.tar.gz
-      - name: Set up Node (16)
+      - name: Set up Node (20)
         uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: Test setup and yarn install
         run: cp config/ci.config.json config/project.json
       - name: Run tests
diff --git a/.github/workflows/test-changed-misc.yml b/.github/workflows/test-changed-misc.yml
index 3e87f5f5584..e189ff4fecf 100644
--- a/.github/workflows/test-changed-misc.yml
+++ b/.github/workflows/test-changed-misc.yml
@@ -31,10 +31,10 @@ jobs:
       with:
         # This makes Actions fetch all Git history so run-changed script can diff properly.
         fetch-depth: 0
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: install Chrome stable
       run: |
         sudo apt-get update
diff --git a/.github/workflows/test-changed.yml b/.github/workflows/test-changed.yml
index f0cf68f7315..ac45286b0c8 100644
--- a/.github/workflows/test-changed.yml
+++ b/.github/workflows/test-changed.yml
@@ -31,10 +31,10 @@ jobs:
         with:
           # This makes Actions fetch all Git history so run-changed script can diff properly.
           fetch-depth: 0
-      - name: Set up Node (16)
+      - name: Set up Node (20)
         uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: install Chrome stable
         run: |
           sudo apt-get update
@@ -60,10 +60,10 @@ jobs:
         uses: actions/checkout@master
         with:
           fetch-depth: 0
-      - name: Set up Node (16)
+      - name: Set up Node (20)
         uses: actions/setup-node@v3
         with:
-          node-version: 16.x
+          node-version: 20.x
       - name: install Firefox stable
         run: |
           sudo apt-get update
diff --git a/.github/workflows/test-firebase-integration.yml b/.github/workflows/test-firebase-integration.yml
index 9eb15ab78d2..f6b1eb3c4b3 100644
--- a/.github/workflows/test-firebase-integration.yml
+++ b/.github/workflows/test-firebase-integration.yml
@@ -31,10 +31,10 @@ jobs:
       with:
         # This makes Actions fetch all Git history so run-changed script can diff properly.
         fetch-depth: 0
-    - name: Set up Node (16)
+    - name: Set up Node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: install Chrome stable
       run: |
         sudo apt-get update
diff --git a/.github/workflows/update-api-reports.yml b/.github/workflows/update-api-reports.yml
index e4f90c98607..f49c548e3cc 100644
--- a/.github/workflows/update-api-reports.yml
+++ b/.github/workflows/update-api-reports.yml
@@ -30,10 +30,10 @@ jobs:
         # checkout HEAD commit instead of merge commit
         ref: ${{ github.event.pull_request.head.ref }}
         token: ${{ github.token }}
-    - name: Set up node (16)
+    - name: Set up node (20)
       uses: actions/setup-node@v3
       with:
-        node-version: 16.x
+        node-version: 20.x
     - name: Yarn install
       run: yarn
     - name: Update API reports
diff --git a/packages/auth/src/core/auth/emulator.test.ts b/packages/auth/src/core/auth/emulator.test.ts
index 8015aecee18..71a30883218 100644
--- a/packages/auth/src/core/auth/emulator.test.ts
+++ b/packages/auth/src/core/auth/emulator.test.ts
@@ -45,7 +45,7 @@ describe('core/auth/emulator', () => {
     fetch.setUp();
     normalEndpoint = mockEndpoint(Endpoint.DELETE_ACCOUNT, {});
     emulatorEndpoint = fetch.mock(
-      `http://localhost:2020/${endpointUrl(Endpoint.DELETE_ACCOUNT).replace(
+      `http://127.0.0.1:2020/${endpointUrl(Endpoint.DELETE_ACCOUNT).replace(
         /^.*:\/\//,
         ''
       )}`,
@@ -70,46 +70,46 @@ describe('core/auth/emulator', () => {
   context('connectAuthEmulator', () => {
     it('fails if a network request has already been made', async () => {
       await user.delete();
-      expect(() => connectAuthEmulator(auth, 'http://localhost:2020')).to.throw(
+      expect(() => connectAuthEmulator(auth, 'http://127.0.0.1:2020')).to.throw(
         FirebaseError,
         'auth/emulator-config-failed'
       );
     });
 
     it('updates the endpoint appropriately', async () => {
-      connectAuthEmulator(auth, 'http://localhost:2020');
+      connectAuthEmulator(auth, 'http://127.0.0.1:2020');
       await user.delete();
       expect(normalEndpoint.calls.length).to.eq(0);
       expect(emulatorEndpoint.calls.length).to.eq(1);
     });
 
     it('updates the endpoint appropriately with trailing slash', async () => {
-      connectAuthEmulator(auth, 'http://localhost:2020/');
+      connectAuthEmulator(auth, 'http://127.0.0.1:2020/');
       await user.delete();
       expect(normalEndpoint.calls.length).to.eq(0);
       expect(emulatorEndpoint.calls.length).to.eq(1);
     });
 
     it('checks the scheme properly', () => {
-      expect(() => connectAuthEmulator(auth, 'http://localhost:2020')).not.to
+      expect(() => connectAuthEmulator(auth, 'http://127.0.0.1:2020')).not.to
         .throw;
       delete auth.config.emulator;
-      expect(() => connectAuthEmulator(auth, 'https://localhost:2020')).not.to
+      expect(() => connectAuthEmulator(auth, 'https://127.0.0.1:2020')).not.to
         .throw;
       delete auth.config.emulator;
-      expect(() => connectAuthEmulator(auth, 'ssh://localhost:2020')).to.throw(
+      expect(() => connectAuthEmulator(auth, 'ssh://127.0.0.1:2020')).to.throw(
         FirebaseError,
         'auth/invalid-emulator-scheme'
       );
       delete auth.config.emulator;
-      expect(() => connectAuthEmulator(auth, 'localhost:2020')).to.throw(
+      expect(() => connectAuthEmulator(auth, '127.0.0.1:2020')).to.throw(
         FirebaseError,
         'auth/invalid-emulator-scheme'
       );
     });
 
     it('attaches a banner to the DOM', () => {
-      connectAuthEmulator(auth, 'http://localhost:2020');
+      connectAuthEmulator(auth, 'http://127.0.0.1:2020');
       if (typeof document !== 'undefined') {
         const el = document.querySelector('.firebase-emulator-warning')!;
         expect(el).not.to.be.null;
@@ -122,7 +122,7 @@ describe('core/auth/emulator', () => {
 
     it('logs out a warning to the console', () => {
       sinon.stub(console, 'info');
-      connectAuthEmulator(auth, 'http://localhost:2020');
+      connectAuthEmulator(auth, 'http://127.0.0.1:2020');
       expect(console.info).to.have.been.calledWith(
         'WARNING: You are using the Auth Emulator,' +
           ' which is intended for local testing only.  Do not use with' +
@@ -132,7 +132,7 @@ describe('core/auth/emulator', () => {
 
     it('skips console info and has no banner if warnings disabled', () => {
       sinon.stub(console, 'info');
-      connectAuthEmulator(auth, 'http://localhost:2020', {
+      connectAuthEmulator(auth, 'http://127.0.0.1:2020', {
         disableWarnings: true
       });
       expect(console.info).not.to.have.been.called;
@@ -142,10 +142,10 @@ describe('core/auth/emulator', () => {
     });
 
     it('sets emulatorConfig on the Auth object', async () => {
-      connectAuthEmulator(auth, 'http://localhost:2020');
+      connectAuthEmulator(auth, 'http://127.0.0.1:2020');
       expect(auth.emulatorConfig).to.eql({
         protocol: 'http',
-        host: 'localhost',
+        host: '127.0.0.1',
         port: 2020,
         options: { disableWarnings: false }
       });
diff --git a/packages/auth/src/core/util/emulator.test.ts b/packages/auth/src/core/util/emulator.test.ts
index 65337681d5b..17a916917b1 100644
--- a/packages/auth/src/core/util/emulator.test.ts
+++ b/packages/auth/src/core/util/emulator.test.ts
@@ -23,23 +23,23 @@ import { _emulatorUrl } from './emulator';
 describe('core/util/emulator', () => {
   const config: ConfigInternal = {
     emulator: {
-      url: 'http://localhost:4000/'
+      url: 'http://127.0.0.1:4000/'
     }
   } as ConfigInternal;
 
   it('builds the proper URL with no path', () => {
-    expect(_emulatorUrl(config)).to.eq('http://localhost:4000/');
+    expect(_emulatorUrl(config)).to.eq('http://127.0.0.1:4000/');
   });
 
   it('builds the proper URL with a path', () => {
     expect(_emulatorUrl(config, '/test/path')).to.eq(
-      'http://localhost:4000/test/path'
+      'http://127.0.0.1:4000/test/path'
     );
   });
 
   it('builds the proper URL with a path missing separator', () => {
     expect(_emulatorUrl(config, 'test/path')).to.eq(
-      'http://localhost:4000/test/path'
+      'http://127.0.0.1:4000/test/path'
     );
   });
 });
diff --git a/packages/auth/src/platform_browser/index.ts b/packages/auth/src/platform_browser/index.ts
index 6399072d713..2d21c768454 100644
--- a/packages/auth/src/platform_browser/index.ts
+++ b/packages/auth/src/platform_browser/index.ts
@@ -89,9 +89,11 @@ export function getAuth(app: FirebaseApp = getApp()): Auth {
     ]
   });
 
-  const authTokenSyncUrl = getExperimentalSetting('authTokenSyncURL');
-  if (authTokenSyncUrl) {
-    const mintCookie = mintCookieFactory(authTokenSyncUrl);
+  const authTokenSyncPath = getExperimentalSetting('authTokenSyncURL');
+  // Don't allow urls (XSS possibility), only paths on the same domain
+  // (starting with '/')
+  if (authTokenSyncPath && authTokenSyncPath.startsWith('/')) {
+    const mintCookie = mintCookieFactory(authTokenSyncPath);
     beforeAuthStateChanged(auth, mintCookie, () =>
       mintCookie(auth.currentUser)
     );
diff --git a/packages/firebase/package.json b/packages/firebase/package.json
index 8a4cd25a02a..35425f5244d 100644
--- a/packages/firebase/package.json
+++ b/packages/firebase/package.json
@@ -16,7 +16,7 @@
     "remote-config"
   ],
   "files": [
-    "**/dist/",
+    "**/dist/**/*",
     "**/package.json",
     "/firebase*.js",
     "/firebase*.map",
diff --git a/packages/firestore/test/integration/api/validation.test.ts b/packages/firestore/test/integration/api/validation.test.ts
index 8260b53bb4f..eb0119b5d39 100644
--- a/packages/firestore/test/integration/api/validation.test.ts
+++ b/packages/firestore/test/integration/api/validation.test.ts
@@ -173,7 +173,7 @@ apiDescribe('Validation:', persistence => {
       () => {
         const db = newTestFirestore(newTestApp('test-project'));
         // Verify that this doesn't throw.
-        connectFirestoreEmulator(db, 'localhost', 9000);
+        connectFirestoreEmulator(db, '127.0.0.1', 9000);
       }
     );
 
@@ -185,7 +185,7 @@ apiDescribe('Validation:', persistence => {
           'Firestore has already been started and its settings can no longer be changed.';
 
         await setDoc(doc(db, 'foo/bar'), {});
-        expect(() => connectFirestoreEmulator(db, 'localhost', 9000)).to.throw(
+        expect(() => connectFirestoreEmulator(db, '127.0.0.1', 9000)).to.throw(
           errorMsg
         );
       }
@@ -197,7 +197,7 @@ apiDescribe('Validation:', persistence => {
       () => {
         const db = newTestFirestore(newTestApp('test-project'));
         // Verify that this doesn't throw.
-        connectFirestoreEmulator(db, 'localhost', 9000, {
+        connectFirestoreEmulator(db, '127.0.0.1', 9000, {
           mockUserToken: { sub: 'foo' }
         });
       }
@@ -209,7 +209,7 @@ apiDescribe('Validation:', persistence => {
       () => {
         const db = newTestFirestore(newTestApp('test-project'));
         // Verify that this doesn't throw.
-        connectFirestoreEmulator(db, 'localhost', 9000, {
+        connectFirestoreEmulator(db, '127.0.0.1', 9000, {
           mockUserToken: 'my-mock-user-token'
         });
       }
@@ -222,7 +222,7 @@ apiDescribe('Validation:', persistence => {
         const errorMsg = "mockUserToken must contain 'sub' or 'user_id' field!";
 
         expect(() =>
-          connectFirestoreEmulator(db, 'localhost', 9000, {
+          connectFirestoreEmulator(db, '127.0.0.1', 9000, {
             mockUserToken: {} as any
           })
         ).to.throw(errorMsg);
diff --git a/packages/firestore/test/unit/api/database.test.ts b/packages/firestore/test/unit/api/database.test.ts
index ddae011b3cb..9dcc7f5ae9d 100644
--- a/packages/firestore/test/unit/api/database.test.ts
+++ b/packages/firestore/test/unit/api/database.test.ts
@@ -547,9 +547,9 @@ describe('Settings', () => {
   it('gets settings from useEmulator', () => {
     // Use a new instance of Firestore in order to configure settings.
     const db = newTestFirestore();
-    connectFirestoreEmulator(db, 'localhost', 9000);
+    connectFirestoreEmulator(db, '127.0.0.1', 9000);
 
-    expect(db._getSettings().host).to.equal('localhost:9000');
+    expect(db._getSettings().host).to.equal('127.0.0.1:9000');
     expect(db._getSettings().ssl).to.be.false;
   });
 
@@ -557,9 +557,9 @@ describe('Settings', () => {
     // Use a new instance of Firestore in order to configure settings.
     const db = newTestFirestore();
     db._setSettings({ host: 'other.host' });
-    connectFirestoreEmulator(db, 'localhost', 9000);
+    connectFirestoreEmulator(db, '127.0.0.1', 9000);
 
-    expect(db._getSettings().host).to.equal('localhost:9000');
+    expect(db._getSettings().host).to.equal('127.0.0.1:9000');
     expect(db._getSettings().ssl).to.be.false;
   });
 
@@ -567,7 +567,7 @@ describe('Settings', () => {
     // Use a new instance of Firestore in order to configure settings.
     const db = newTestFirestore();
     const mockUserToken = { sub: 'foobar' };
-    connectFirestoreEmulator(db, 'localhost', 9000, { mockUserToken });
+    connectFirestoreEmulator(db, '127.0.0.1', 9000, { mockUserToken });
 
     const credentials = db._authCredentials;
     expect(credentials).to.be.instanceOf(EmulatorAuthCredentialsProvider);
@@ -579,7 +579,7 @@ describe('Settings', () => {
   it('sets credentials based on mockUserToken string', async () => {
     // Use a new instance of Firestore in order to configure settings.
     const db = newTestFirestore();
-    connectFirestoreEmulator(db, 'localhost', 9000, {
+    connectFirestoreEmulator(db, '127.0.0.1', 9000, {
       mockUserToken: 'my-custom-mock-user-token'
     });
 
diff --git a/packages/rules-unit-testing/functions/package.json b/packages/rules-unit-testing/functions/package.json
index c701103ae64..54fd69653b5 100644
--- a/packages/rules-unit-testing/functions/package.json
+++ b/packages/rules-unit-testing/functions/package.json
@@ -12,6 +12,6 @@
     "firebase-functions": "3.24.1"
   },
   "engines": {
-    "node": "16"
+    "node": ">=16"
   }
 }
diff --git a/scripts/emulator-testing/emulators/emulator.ts b/scripts/emulator-testing/emulators/emulator.ts
index d56226842eb..1295d413e4b 100644
--- a/scripts/emulator-testing/emulators/emulator.ts
+++ b/scripts/emulator-testing/emulators/emulator.ts
@@ -119,8 +119,8 @@ export abstract class Emulator {
         if (elapsed > timeout) {
           reject(`Emulator not ready after ${timeout}s. Exiting ...`);
         } else {
-          console.log(`Ping emulator at [http://localhost:${this.port}] ...`);
-          fetch(`http://localhost:${this.port}`).then(
+          console.log(`Ping emulator at [http://127.0.0.1:${this.port}] ...`);
+          fetch(`http://127.0.0.1:${this.port}`).then(
             () => {
               // Database and Firestore emulators will return 400 and 200 respectively.
               // As long as we get a response back, it means the emulator is ready.