---
title: Agents that browse with Playwright 1.64 run Chromium 156.0.8078.4, a build from before Chrome's Oct 27 fix for four critical bugs including CVE-2026-118306, and Playwright's Chromium sandbox is off by default | ctxsec
url: https://ctxsec.com/items/playwright-1-64-bundled-chromium-156-0-8078-4-predates-oct-27-chrome-fixes
description: "Playwright's latest release, 1.64.1, still downloads Chromium 156.0.8078.4, the build that shipped with 1.64.0 on Oct 7. Google's Oct 27 Chrome stable update (156.0.8078.73/.74) fixed 52 security bugs, four of them critical, including CVE-2026-118306, a FileSystem memory-corruption bug that can let a crafted page run code outside the sandbox. Playwright's documentation says its chromiumSandbox launch option defaults to false. AI coding and browsing agents that use Playwright's bundled browser on untrusted pages are therefore running an older engine with the sandbox off. A developer alert on X on Nov 2 drew attention to this; the facts below come from Playwright's and Google's own pages."
status: "official (Playwright v1.64.0 release notes and v1.64.1 browsers.json; Chrome Releases Oct 27 stable update; Playwright docs on chromiumSandbox). Not a Playwright CVE; no exploitation of these Chrome bugs reported"
published: 2026-11-02
---

> Playwright's latest release, 1.64.1, still downloads Chromium 156.0.8078.4, the build that shipped with 1.64.0 on Oct 7. Google's Oct 27 Chrome stable update (156.0.8078.73/.74) fixed 52 security bugs, four of them critical, including CVE-2026-118306, a FileSystem memory-corruption bug that can let a crafted page run code outside the sandbox. Playwright's documentation says its chromiumSandbox launch option defaults to false. AI coding and browsing agents that use Playwright's bundled browser on untrusted pages are therefore running an older engine with the sandbox off. A developer alert on X on Nov 2 drew attention to this; the facts below come from Playwright's and Google's own pages.

[← Context & Harness Attacks](/context) · [markdown](/items/playwright-1-64-bundled-chromium-156-0-8078-4-predates-oct-27-chrome-fixes.md)

official (Playwright v1.64.0 release notes and v1.64.1 browsers.json; Chrome Releases Oct 27 stable update; Playwright docs on chromiumSandbox). Not a Playwright CVE; no exploitation of these Chrome bugs reported

2026-11-02

### Agents that browse with Playwright 1.64 run Chromium 156.0.8078.4, a build from before Chrome's Oct 27 fix for four critical bugs including CVE-2026-118306, and Playwright's Chromium sandbox is off by default

- **Bundled build:** Playwright v1.64.0 release notes list Chromium **156.0.8078.4**; the v1.64.1 browsers.json pins the same version. Playwright's main branch has already rolled to Chromium 158.0.8127.2, which has not shipped in a release yet.
- **What it misses:** Chrome 156.0.8078.73/.74 (Oct 27) fixed 52 flaws, including critical CVE-2026-118306 (FileSystem memory corruption, CVSS 3.1 9.6, code execution outside the sandbox via a crafted HTML page), CVE-2026-118331, CVE-2026-118348 and CVE-2026-118344. Google did not report any of them as exploited.
- **Sandbox default:** Playwright's API docs say `chromiumSandbox` is false by default, so renderer exploits are not contained by Chromium's sandbox unless you turn it on.

**What to do if your agents use Playwright to browse untrusted sites:** launch with `chromiumSandbox: true`, or point Playwright at an up-to-date installed Chrome with `channel: 'chrome'`; run the agent's browser in a disposable VM or container without your credentials; and update when Playwright releases a newer Chromium. Test suites that only load your own app carry much less risk.

Sources: [Playwright v1.64.0 release notes (Chromium 156.0.8078.4)](https://github.com/microsoft/playwright/releases/tag/v1.64.0) · [Playwright v1.64.1 browsers.json](https://github.com/microsoft/playwright/blob/v1.64.1/packages/playwright-core/browsers.json) · [Playwright docs: chromiumSandbox defaults to false](https://playwright.dev/docs/api/class-browsertype) · [Chrome Releases: Stable Channel Update for Desktop (Oct 27)](https://chromereleases.googleblog.com/2026/10/stable-channel-update-for-desktop_0562499947.html) · [CVE-2026-118306 record](https://www.cve.org/CVERecord?id=CVE-2026-118306)