OpenClaw versions before 2026.3.23 expose a flaw in the Canvas gateway where the function authorizeCanvasRequest bypasses authentication checks for local‑direct HTTP and WebSocket traffic. This allows attackers to send loopback requests to Canvas routes without bearer tokens or canvas capability validation, leading to unauthorized access. The weakness aligns with CWE‑288, indicating a loss of authentication.

Affected is the OpenClaw platform with the OpenClaw product. All installations running any version earlier than 2026.3.23 are vulnerable. The issue is specific to the Canvas gateway component of OpenClaw and does not affect other modules directly.

The CVSS score of 5.1 indicates moderate severity. The EPSS score is not available, and the vulnerability is not listed in the CISA KEV catalog. The likely attack vector requires an attacker to be able to issue local‑direct requests, either by having local system access or through an exploitation channel that trusts loopback traffic. Once gained, unauthorized requests can reach protected Canvas endpoints, potentially exposing sensitive data or enabling further system compromise depending on the privileges of those routes.