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Microsoft issued a patch for its supported systems in March , weeks before Shadow Brokers released the exploit , but many computer systems around the world remained unpatched , leaving them vulnerable to the latest ransomware attack .
 ( patch vulnerability: issued,  a patch: patch, Microsoft: releaser, systems: vulnerable system, March: time) 
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:
 ( patch vulnerability: issued,  a patch: patch, Microsoft: releaser, systems: vulnerable system, March: time) 