diff --git a/README.md b/README.md
index 324f49bd4234e..bd0475b65fe97 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # 🎭 Playwright
 
-[![npm version](https://img.shields.io/npm/v/playwright.svg)](https://www.npmjs.com/package/playwright) <!-- GEN:chromium-version-badge -->[![Chromium version](https://img.shields.io/badge/chromium-151.0.7922.10-blue.svg?logo=google-chrome)](https://www.chromium.org/Home)<!-- GEN:stop --> <!-- GEN:firefox-version-badge -->[![Firefox version](https://img.shields.io/badge/firefox-151.0-blue.svg?logo=firefoxbrowser)](https://www.mozilla.org/en-US/firefox/new/)<!-- GEN:stop --> <!-- GEN:webkit-version-badge -->[![WebKit version](https://img.shields.io/badge/webkit-26.5-blue.svg?logo=safari)](https://webkit.org/)<!-- GEN:stop --> [![Join Discord](https://img.shields.io/badge/join-discord-informational)](https://aka.ms/playwright/discord)
+[![npm version](https://img.shields.io/npm/v/playwright.svg)](https://www.npmjs.com/package/playwright) <!-- GEN:chromium-version-badge -->[![Chromium version](https://img.shields.io/badge/chromium-151.0.7922.10-blue.svg?logo=google-chrome)](https://www.chromium.org/Home)<!-- GEN:stop --> <!-- GEN:firefox-version-badge -->[![Firefox version](https://img.shields.io/badge/firefox-152.0.4-blue.svg?logo=firefoxbrowser)](https://www.mozilla.org/en-US/firefox/new/)<!-- GEN:stop --> <!-- GEN:webkit-version-badge -->[![WebKit version](https://img.shields.io/badge/webkit-26.5-blue.svg?logo=safari)](https://webkit.org/)<!-- GEN:stop --> [![Join Discord](https://img.shields.io/badge/join-discord-informational)](https://aka.ms/playwright/discord)
 
 ## [Documentation](https://playwright.dev) | [API reference](https://playwright.dev/docs/api/class-playwright)
 
@@ -298,7 +298,7 @@ The [Playwright VS Code extension](https://marketplace.visualstudio.com/items?it
 |   :---   | :---: | :---: | :---:   |
 | Chromium<sup>1</sup> <!-- GEN:chromium-version -->151.0.7922.10<!-- GEN:stop --> | :white_check_mark: | :white_check_mark: | :white_check_mark: |
 | WebKit <!-- GEN:webkit-version -->26.5<!-- GEN:stop --> | :white_check_mark: | :white_check_mark: | :white_check_mark: |
-| Firefox <!-- GEN:firefox-version -->151.0<!-- GEN:stop --> | :white_check_mark: | :white_check_mark: | :white_check_mark: |
+| Firefox <!-- GEN:firefox-version -->152.0.4<!-- GEN:stop --> | :white_check_mark: | :white_check_mark: | :white_check_mark: |
 
 Headless and headed execution on all platforms. <sup>1</sup> Uses [Chrome for Testing](https://developer.chrome.com/blog/chrome-for-testing) by default.
 
diff --git a/packages/isomorphic/deviceDescriptorsSource.json b/packages/isomorphic/deviceDescriptorsSource.json
index 098f5cb0f29c0..cc021dc9b27a0 100644
--- a/packages/isomorphic/deviceDescriptorsSource.json
+++ b/packages/isomorphic/deviceDescriptorsSource.json
@@ -2662,7 +2662,7 @@
     "defaultBrowserType": "chromium"
   },
   "Desktop Firefox HiDPI": {
-    "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:151.0) Gecko/20100101 Firefox/151.0",
+    "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:152.0.4) Gecko/20100101 Firefox/152.0.4",
     "screen": {
       "width": 1792,
       "height": 1120
@@ -2722,7 +2722,7 @@
     "defaultBrowserType": "chromium"
   },
   "Desktop Firefox": {
-    "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:151.0) Gecko/20100101 Firefox/151.0",
+    "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:152.0.4) Gecko/20100101 Firefox/152.0.4",
     "screen": {
       "width": 1920,
       "height": 1080
diff --git a/packages/playwright-core/browsers.json b/packages/playwright-core/browsers.json
index 261420d8fe256..a63a6f5baf709 100644
--- a/packages/playwright-core/browsers.json
+++ b/packages/playwright-core/browsers.json
@@ -31,9 +31,9 @@
     },
     {
       "name": "firefox",
-      "revision": "1533",
+      "revision": "1534",
       "installByDefault": true,
-      "browserVersion": "151.0",
+      "browserVersion": "152.0.4",
       "title": "Firefox"
     },
     {
diff --git a/packages/playwright/src/common/config.ts b/packages/playwright/src/common/config.ts
index 4dd22b11d8e81..fc4e378625ea5 100644
--- a/packages/playwright/src/common/config.ts
+++ b/packages/playwright/src/common/config.ts
@@ -221,8 +221,13 @@ function resolveReporters(reporters: Config['reporter'], rootDir: string): Repor
 function resolveWorkers(workers: string | number): number {
   if (typeof workers === 'string') {
     if (workers.endsWith('%')) {
+      const percent = parseInt(workers, 10);
+      if (isNaN(percent))
+        throw new Error(`Workers ${workers} must be a number or percentage.`);
+      if (percent < 1)
+        throw new Error(`Workers must be a positive number, received ${percent}.`);
       const cpus = os.cpus().length;
-      return Math.max(1, Math.floor(cpus * (parseInt(workers, 10) / 100)));
+      return Math.max(1, Math.floor(cpus * (percent / 100)));
     }
     const parsedWorkers = parseInt(workers, 10);
     if (isNaN(parsedWorkers))
diff --git a/tests/playwright-test/config.spec.ts b/tests/playwright-test/config.spec.ts
index ab04bf8970c03..9c4acda6e445a 100644
--- a/tests/playwright-test/config.spec.ts
+++ b/tests/playwright-test/config.spec.ts
@@ -573,6 +573,18 @@ test('should throw when workers is negative via CLI (regression for #39938)', as
   expect(result.output).toContain('Workers must be a positive number');
 });
 
+test('should throw when workers is an invalid percentage via CLI (regression for #41679)', async ({ runInlineTest }) => {
+  const result = await runInlineTest({
+    'playwright.config.ts': `module.exports = {};`,
+    'a.test.ts': `
+      import { test, expect } from '@playwright/test';
+      test('fails', () => { expect(1).toBe(2); });
+    `,
+  }, { workers: 'abc%' });
+  expect(result.exitCode).toBe(1);
+  expect(result.output).toContain('Workers abc% must be a number or percentage.');
+});
+
 test('should work with undefined values and base', async ({ runInlineTest }) => {
   const result = await runInlineTest({
     'playwright.config.ts': `