An exploit broker is an individual or organization that specializes in buying, selling, or trading software vulnerabilities and exploits. These brokers act as intermediaries between those who discover vulnerabilities (such as security researchers or hackers) and clients interested in acquiring them, which may include governments, intelligence agencies, or cybercriminal groups. Exploit brokers often operate in secrecy and may deal in both zero-day exploits - vulnerabilities unknown to the software vendor - and known vulnerabilities for which no public exploit exists. Their activities can have significant implications for cybersecurity, as they may enable targeted attacks, surveillance, or cyber espionage.