Update Playwright and its AI browser tool on your computer
Older Playwright versions downloaded browsers without checking certificates, and older Playwright MCP servers could be reached by websites you visit, so update both and refresh their browsers.
What happened
Playwright versions before 1.55.1 downloaded browsers without checking security certificates, which allowed others on your network to provide tampered files. A flaw in the Playwright MCP server also let external websites control your browser through DNS rebinding. These issues are now fixed in the latest releases.
Who is affected
You are affected if you use Playwright below 1.55.1 or the Playwright MCP server below 0.0.40. Playwright uses its own copy of Chromium, so an outdated Playwright also means an outdated browser that misses the security fixes Chrome has shipped since. Developers running local servers on all network interfaces can also be reached by others on the same Wi-Fi.
Why it matters if you build with AI
AI assistants use these tools to browse the web on your behalf, so a flaw here gives an unauthorised site direct control over your automation. If your MCP server is exposed, a website you visit could drive your browser to perform actions as you. Keeping these tools updated and reachable only from your own computer helps your AI agent work for you alone.
What to do
- Update Playwright and @playwright/mcp to current versions and pin exact versions.
- Reinstall Playwright browsers so old copies are removed.
- Run AI browser tools over standard input and output or bound to localhost only.
- Make development servers listen on localhost only or block incoming connections in your firewall.
Locaas is being built to track advisories like this, check your running applications and propose the necessary updates for your approval.
Get early access