Security fixes target the current main branch and the latest tagged release.

Open a private security advisory on GitHub when possible. If that is not available, contact the maintainer through the GitHub profile linked in the README.

Please include:

• The affected version or commit.
• Reproduction steps.
• The expected browser, relay, and tab attachment state.
• Any proof-of-concept code needed to demonstrate the boundary issue.

Agent Browser Relay is designed for local, human-approved browser access:

• The relay listens on localhost by default.
• The extension can attach only after the human loads the extension and approves the target tab from the popup.
• Agent runs must use --tab-id so commands are scoped to an explicitly attached tab lease.
• The relay exposes CDP methods needed for page reads, screenshots, tab creation, and cleanup. Treat attached tabs as sensitive because they may contain authenticated sessions.
• If a page presents CAPTCHA or human verification, agents must stop and wait for human confirmation before continuing.

Do not expose the relay port to untrusted networks.