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Tavis Ormandy announced during the weekend that he and another Project Zero researcher Natalie Silvanovich discovered " the worst Windows remote code [ execution vulnerability ] in recent memory .
 ( discover vulnerability: discovered,  Project Zero researcher Natalie Silvanovich: discoverer, Tavis Ormandy: discoverer, he: discoverer, the weekend: time, execution vulnerability: vulnerability) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: phishing, data breach, ransom, discover vulnerability, patch vulnerability, Arguments type: vulnerable system, capabilities, vulnerability, number of victim, issues addressed, compromised data, damage amount, common vulnerabilities and exposures, victim, patch number, number of data, tool, discoverer, time, purpose, place, payment method, releaser, vulnerable system version, attacker, supported platform, patch, price, vulnerable system owner, trusted entity, attack pattern. 
Text: {0} 
Answer:
 ( discover vulnerability: discovered,  Project Zero researcher Natalie Silvanovich: discoverer, Tavis Ormandy: discoverer, he: discoverer, the weekend: time, execution vulnerability: vulnerability) 