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The vulnerability lay in the certificate pinning technology , a security mechanism used to prevent impersonation attacks and use of fraudulent certificates by only accepting certificates signed by a single pinned CA root certificate .
 discover vulnerability: lay in
Please tell me event type and its trigger word from given type options. Output format is "type: trigger".  Option: phishing, data breach, ransom, discover vulnerability, patch vulnerability 
Text: {0} 
Answer:
 discover vulnerability: lay in