From cc45753c6ced902a95fcbee989baca5b8776816d Mon Sep 17 00:00:00 2001
From: Devin Rousso <devinrousso@microsoft.com>
Date: Thu, 13 Aug 2026 10:37:23 -0600
Subject: [PATCH] test(clipboard): check that the headless clipboard is
 isolated from the operating system (#42039)

headless WebKit has started using the operating system clipboard in builds `2334` and `2345`, allowing browser instances to read clipboard contents from outside the process

add a test that launches two headless browsers and expects each to read only what it wrote through `navigator.clipboard`

fixes <https://github.com/microsoft/playwright/issues/13097>
---
 tests/library/permissions.spec.ts | 35 ++++++++++++++++++++++++++++---
 tests/mcp/clipboard.spec.ts       |  5 +++--
 2 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/tests/library/permissions.spec.ts b/tests/library/permissions.spec.ts
index d66340f46e85d..64a414296aa7a 100644
--- a/tests/library/permissions.spec.ts
+++ b/tests/library/permissions.spec.ts
@@ -192,11 +192,9 @@ it.describe('permissions', () => {
   });
 });
 
-it('should support clipboard read', async ({ page, context, server, browserName, isWindows, isLinux, headless, isHeadlessShell }) => {
+it('should support clipboard read', async ({ page, context, server, browserName, isWindows, isHeadlessShell }) => {
   it.info().annotations.push({ type: 'issue', description: 'https://github.com/microsoft/playwright/issues/27475' });
   it.fail(browserName === 'firefox', 'No such permissions (requires flag) in Firefox');
-  it.fixme(browserName === 'webkit' && isWindows, 'WebPasteboardProxy::allPasteboardItemInfo not implemented for Windows.');
-  it.fixme(browserName === 'webkit' && isLinux && headless, 'WebPasteboardProxy::allPasteboardItemInfo not implemented for WPE.');
 
   await page.goto(server.EMPTY_PAGE);
   // There is no 'clipboard-read' permission in WebKit Web API.
@@ -219,6 +217,37 @@ it('should support clipboard read', async ({ page, context, server, browserName,
   expect(await page.evaluate(() => navigator.clipboard.readText())).toBe('test content');
 });
 
+it('should isolate the headless clipboard from the operating system', {
+  annotation: { type: 'issue', description: 'https://github.com/microsoft/playwright/issues/13097' },
+}, async ({ browserType, server, browserName, isFrozenWebkit }) => {
+  it.skip(isFrozenWebkit, 'needs recent webkit');
+
+  // Each headless browser gets its own clipboard, so neither can see the clipboard of the operating system nor of another browser.
+  const browser1 = await browserType.launch({ headless: true });
+  const browser2 = await browserType.launch({ headless: true });
+  const [page1, page2] = await Promise.all([browser1, browser2].map(async browser => {
+    const context = await browser.newContext();
+    // There is no 'clipboard-write' permission in WebKit Web API and no clipboard permission at all in Firefox.
+    if (browserName === 'chromium')
+      await context.grantPermissions(['clipboard-read', 'clipboard-write']);
+    else if (browserName === 'webkit')
+      await context.grantPermissions(['clipboard-read']);
+    const page = await context.newPage();
+    await page.goto(server.EMPTY_PAGE);
+    return page;
+  }));
+
+  await page1.evaluate(() => navigator.clipboard.writeText('first'));
+  expect(await page1.evaluate(() => navigator.clipboard.readText())).toBe('first');
+
+  await page2.evaluate(() => navigator.clipboard.writeText('second'));
+  expect(await page2.evaluate(() => navigator.clipboard.readText())).toBe('second');
+
+  expect(await page1.evaluate(() => navigator.clipboard.readText())).toBe('first');
+
+  await Promise.all([browser1.close(), browser2.close()]);
+});
+
 it('storage access', {
   annotation: { type: 'issue', description: 'https://github.com/microsoft/playwright/issues/31227' }
 }, async ({ page, context, server, browserName }) => {
diff --git a/tests/mcp/clipboard.spec.ts b/tests/mcp/clipboard.spec.ts
index 264948b924474..051939050aae4 100644
--- a/tests/mcp/clipboard.spec.ts
+++ b/tests/mcp/clipboard.spec.ts
@@ -17,9 +17,10 @@
 import { test, expect } from './fixtures';
 
 test('clipboard write without permission dialog', async ({ startClient, server, mcpBrowser }) => {
-  test.skip(mcpBrowser === 'firefox' || mcpBrowser === 'webkit', 'Clipboard permissions are fully supported only in Chromium');
+  test.skip(mcpBrowser === 'firefox', 'No such permissions (requires flag) in Firefox');
+  const permissions = mcpBrowser === 'webkit' ? 'clipboard-read' : 'clipboard-read,clipboard-write';
   const { client } = await startClient({
-    args: [`--grant-permissions=clipboard-read,clipboard-write`]
+    args: [`--grant-permissions=${permissions}`]
   });
   await client.callTool({
     name: 'browser_navigate',