The term "zero-day vulnerability" refers specifically to a security flaw that is unknown to the software vendor and remains unpatched. This type of vulnerability is extremely critical because, until the vendor learns about it and develops a fix, it can be exploited by attackers without any warning. The “zero-day” aspect denotes that there has been zero days of time for the vendor to address the vulnerability, making it a particularly dangerous threat within the cybersecurity landscape.
Once a zero-day vulnerability is discovered, it may be targeted by cybercriminals, leading to potential data breaches, system compromises, or other malicious actions. Because no patch exists at the moment the vulnerability is exploited, the risk it poses is heightened, emphasizing the need for organizations to maintain robust monitoring and intrusion detection systems to mitigate potential attacks on such vulnerabilities.