A critical authentication vulnerability in the OpenClaw Browser Relay allows unauthenticated attackers to hijack sessions and execute unauthorized JavaScript within the user browser.

The vulnerability exists in the Browser Relay WebSocket endpoint (/cdp) which fails to enforce authentication tokens. This allows malicious websites to connect to the local loopback interface, enabling attackers to steal session cookies and execute arbitrary JavaScript in other open browser tabs.

The ability to steal session cookies and execute JavaScript in the context of other browser tabs poses a severe risk to organizational security. Successful exploitation could lead to full account takeover, unauthorized access to internal SaaS applications, and the theft of sensitive proprietary data. Given the CVSS score of 8.1, this vulnerability represents a high risk to business operations and data integrity.

Immediate Action: Update the OpenClaw package to version 2026.2.1 or later immediately to apply the required authentication checks.

Proactive Monitoring: Review browser extension logs and monitor for unexpected WebSocket connections targeting the local loopback address on port 18792.

Compensating Controls: If an immediate update is not feasible, disable the OpenClaw Browser Relay extension entirely to eliminate the exposed attack surface.

Public Exploit Available: Unknown.

The severity of this vulnerability necessitates immediate action, as it provides a direct path for attackers to bypass browser security boundaries. Administrators and end users should prioritize updating to version 2026.2.1 to ensure that mandatory authentication tokens are enforced for all WebSocket communications, thereby preventing unauthorized access to sensitive session data.