CVE-2026-28458 in OpenClaw
Summary
by MITRE • 03/06/2026
OpenClaw version 2026.1.20 prior to 2026.2.1 contains a vulnerability in the Browser Relay (extension must be installed and enabled) /cdp WebSocket endpoint in which it does not require authentication tokens, allowing websites to connect via loopback and access sensitive data. Attackers can exploit this by connecting to ws://127.0.0.1:18792/cdp to steal session cookies and execute JavaScript in other browser tabs.
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Analysis
by VulDB Data Team • 03/10/2026
The vulnerability identified as CVE-2026-28458 affects OpenClaw version 2026.1.20 and earlier, specifically targeting the Browser Relay extension functionality that operates through the /cdp WebSocket endpoint. This flaw represents a critical security oversight in the application's network communication architecture, where authentication mechanisms have been completely bypassed for local network connections. The vulnerability exists within the extension's WebSocket interface that listens on the loopback address 127.0.0.1 at port 18792, creating an attack surface that allows unauthorized access to sensitive browser data without proper authorization checks.
The technical implementation of this vulnerability stems from the absence of authentication token validation within the WebSocket endpoint, which is designed to facilitate communication between browser tabs and the local application. When the Browser Relay extension is installed and enabled, it establishes a WebSocket connection to the local endpoint that should normally require proper authentication. However, the lack of authentication requirements means that any website or malicious actor with access to the local network can establish a connection to ws://127.0.0.1:18792/cdp and gain unrestricted access to the browser's debugging protocol. This design flaw aligns with CWE-306, which addresses missing authentication mechanisms, and represents a significant failure in the principle of least privilege for local network services.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables sophisticated attack vectors that can compromise user sessions and browser integrity. Attackers can exploit this weakness to steal session cookies from other browser tabs, effectively hijacking user sessions and gaining unauthorized access to protected web applications. The ability to execute JavaScript within other browser tabs creates a severe cross-site scripting scenario where malicious code can manipulate browser behavior, capture user interactions, and potentially exfiltrate sensitive data. This vulnerability directly maps to ATT&CK technique T1059.007 for JavaScript execution and T1531 for credential access through session hijacking, making it particularly dangerous in environments where users maintain multiple active sessions.
Mitigation strategies for this vulnerability should focus on immediate remediation through the installation of OpenClaw version 2026.2.1 or later, which addresses the authentication bypass issue. Security administrators should implement network segmentation to restrict local network access to the affected port and consider disabling the Browser Relay extension for users who do not require its functionality. Additional protective measures include implementing proper authentication tokens for WebSocket connections, enforcing strict access controls on loopback interfaces, and conducting regular security assessments of browser extensions. Organizations should also consider deploying web application firewalls to monitor and block unauthorized WebSocket connections to local endpoints, while ensuring that browser extensions are regularly updated and reviewed for security compliance. The vulnerability serves as a reminder of the critical importance of authentication mechanisms in local network services and the potential for seemingly benign features to create significant security risks when proper access controls are not implemented.