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At first , the researchers accidentally discovered CVE -2018-16864 while working on an exploit for a previously disclosed vulnerability , Mutagen Astronomy .
 the researchers: discoverer; CVE -2018-16864: common vulnerabilities and exposures; a previously disclosed vulnerability: vulnerability
Given event type and trigger, please tell me the arguments of all the listed option. Output format is "name1: role1; name2: role2". 
Event type: discover vulnerability 
  Option: vulnerable system owner, vulnerability, capabilities, time, vulnerable system version, discoverer, common vulnerabilities and exposures, supported platform, vulnerable system 
Text: {0} 
Answer:
 the researchers: discoverer; CVE -2018-16864: common vulnerabilities and exposures; a previously disclosed vulnerability: vulnerability