A missing authentication requirement in OpenClaw’s Browser Relay /cdp WebSocket endpoint allows any web page loaded in a user’s browser to connect to the local ws://127.0.0.1:18792/cdp socket. By doing so, attackers can steal session cookies and inject arbitrary JavaScript into other open browser tabs, effectively hijacking the user’s session and compromising the confidentiality and integrity of the browser context.

The vulnerability affects the OpenClaw application, specifically versions 2026.1.20 and earlier that are prior to 2026.2.1. It requires the Browser Relay extension to be installed and enabled. Users running these versions on a Node.js environment are potentially vulnerable.

The CVSS score of 7.4 indicates a high severity vulnerability, while the EPSS score of less than 1% suggests a very low current exploitation probability. The flaw is not listed in CISA’s KEV catalog. According to the description, the likely attack vector is a malicious webpage that can open a WebSocket connection to the local loopback endpoint, allowing an attacker to read cookie data and execute malicious scripts in the victim’s browser, but it does not provide arbitrary code execution on the host system.