Puppeteer v25.9.0 rolls Firefox 154.0 and Chrome 152.0, adds shadow root support in MutationPoller

Puppeteer released version 25.9.0 of puppeteer-core, updating browser versions and adding support for shadow roots in MutationPoller and tool execution cancellation in webmcp.

Markdown twin JSON

Open Source & Tooling Primary source release / significance 2

Briefing

Puppeteer: Puppeteer released version 25.9.0 of puppeteer-core, updating browser versions and adding support for shadow roots in MutationPoller and tool execution cancellation in webmcp.

Why it matters

This is a routine maintenance release that keeps Puppeteer aligned with the latest Firefox and Chrome builds, ensuring compatibility for users relying on the library for browser automation. The addition of shadow root support in MutationPoller is a minor but useful improvement for scraping or testing within Shadow DOM, while the webmcp cancellation feature offers better control for agent-based workflows.

Sources

Primary source · Puppeteer · 2026-08-25 — puppeteer/puppeteer puppeteer-core: v25.9.0

Watch next

Will Puppeteer add further Shadow DOM enhancements or expand webmcp capabilities in upcoming releases?

Topics: Puppeteer, Firefox, Chrome, puppeteer, browser-automation, release, firefox, chrome, shadow-dom, webmcp