OpenClaw versions prior to 2026.2.14 contain a webhook signature-verification bypass in the voice-call extension that allows unauthenticated requests when the tunnel.allowNgrokFreeTierLoopbackBypass option is explicitly enabled. An external attacker can send forged requests to the publicly reachable webhook endpoint without a valid X-Twilio-Signature header, resulting in unauthorized webhook event handling and potential request flooding attacks.
Exploitability
AV:NAC:LAT:PPR:NUI:NVulnerable System
VC:NVI:LVA:LSubsequent System
SC:NSI:NSA:N6.3/CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:NAuthentication