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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
Low
Partial data modification
Availability
Low
Partial disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 3
https://github.com/openclaw/openclaw/commit/ff11d8793b90c52f8d84dae3fbb99307da5…
disclosure@vulncheck.com
https://github.com/openclaw/openclaw/security/advisories/GHSA-c37p-4qqg-3p76
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/openclaw-webhook-signature-verification-by…
disclosure@vulncheck.com