An application vulnerability is a flaw or weakness in software that can be exploited by malicious actors to compromise system security or data. These vulnerabilities arise from various sources including insecure coding practices, insufficient input validation, broken authentication mechanisms, outdated components, or misconfigurations within an application's code, architecture, or operational environment. Common examples include SQL injection, cross-site scripting (XSS), buffer overflows, and insecure direct object references.

When left unaddressed, application vulnerabilities provide entry points for attackers to gain unauthorized access, steal sensitive data, escalate privileges, or disrupt services entirely. The consequences can severely impact the confidentiality, integrity, and availability of digital assets and user information. Organizations must implement proactive security measures such as regular vulnerability assessments, secure coding practices, penetration testing, and timely patching to identify and remediate these weaknesses before they can be exploited by cyber threats.