A Zero-Day Vulnerability is a software security flaw or vulnerability that is unknown to the software vendor or developer and has not been patched or mitigated before being exploited by attackers. Zero-day vulnerabilities pose significant cybersecurity risks because attackers can leverage them to launch targeted attacks, malware campaigns, or cyber espionage activities before security patches or updates are available. Zero-day exploits can target operating systems, applications, firmware, or hardware components, allowing attackers to gain unauthorized access, execute arbitrary code, escalate privileges, or compromise systems without detection or mitigation.