OpenClaw versions before 2026.2.14 have a bypass in the voice‑call extension that allows an attacker to send requests to the publicly exposed webhook endpoint without supplying a valid X‑Twilio‑Signature header. Because the verification logic is disabled when the tunnel.allowNgrokFreeTierLoopbackBypass option is enabled, the webhook processes forged events as legitimate, enabling an attacker to trigger arbitrary webhook actions or flood the endpoint with unwanted traffic. This flaw is a missing authentication vulnerability (CWE‑306).

Any OpenClaw installation using the voice‑call extension and running a version earlier than 2026.2.14 is vulnerable. The affected products are identified as OpenClaw:OpenClaw and the vulnerability applies to all CPE strings matching cpe:2.3:a:openclaw:openclaw:*:*:*:*:*:node.js:*:*.

The CVSS score of 6.3 indicates a moderate severity, while the EPSS score of less than 1% suggests a low probability of exploitation in the near term. The flaw is not listed in the CISA KEV catalog, further reducing its current exposure. Attackers can exploit the vulnerability remotely by sending crafted webhook events to the public endpoint; no authentication or privileged access is required beyond knowing the URL. If the bypass option is enabled, the attack can affect all users of the affected OpenClaw instance, potentially leading to denial of service or unauthorized processing of events.